Filmmaker Finds An Unlikely Underwater Friend In 'My Octopus Teacher' | CAI

Filmmaker Finds An Unlikely Underwater Friend In 'My Octopus Teacher'

Oct 15, 2020
Originally published on October 15, 2020 4:10 pm

A few years ago, South African documentary filmmaker Craig Foster felt burnt out from years of working on arduous nature films. Needing a reset, he returned to the underwater kelp forests off the southwest tip of Cape Town.

"My earliest memories, my deepest and most powerful memories were of this incredible coast and diving in what I call 'my magical childhood forest,' " Foster says. "It is one of the greatest ecosystems on this planet."

Foster vowed to dive — without a wetsuit or oxygen tank — every day for a year into the chilly waters near where he grew up. The ocean was sometimes as cold as 46 degrees, but his body gradually adapted.

"Day after day, I slowly started to get my energy back and realized that there was this whole new way of looking at this underwater forest. And I started to come alive again," he says.

The waters were teeming with sea creatures, but Foster says his encounters with one particular octopus stood out. Over a series of dives, the octopus began coming out of her den to hunt or explore while Foster watched.

"That's when I realized: This animal trusts me. She no longer sees me as a threat, and her fear changes to curiosity," he says. "That's when the real excitement comes and you think, 'Oh, my goodness, I'm being let into the secret world of this wild animal' — and that's when you feel on fire."

Foster chronicles his underwater encounters in the kelp forest in the new Netflix film, My Octopus Teacher, and the book, Sea Change.


Interview highlights

On the dangers of diving off the western cape of South Africa

I have come very close a few times to losing my life. ... I've been sucked into underwater caves. - Craig Foster

It's called the "Cape of Storms" for a good reason — enormous waves and some of the biggest surfing waves in the world. And people are scared of sharks and big animals and that kind of thing, which aren't actually really a danger at all. But the one thing that is very dangerous are these enormous seas. And I have come very close a few times to losing my life and I've been sucked into underwater caves. ... So if you're dedicated to diving every day, especially, you have to be very, very careful and try to read the weather very well, try to read the currents and then don't venture into those very dangerous places during those times. There's always some little place you can find to get in, which is relatively safe, but it took a while to learn exactly how to do that.

On why he chooses to free dive — without a wetsuit or oxygen — in these extremely cold waters

You feel alive, you feel awake, you feel stimulated. But because you can feel that water on your skin, you can feel the slight temperature differences, you feel much closer to nature. You feel more amphibious, in a way. I like to ponder on the amphibious nature of our humanness and diving in this way, with this method, brings out that amphibious nature.

At first, it took me quite a long time [to get used to the cold]. ... I remember shivering for about a year, every day. And then one day, I just stopped shivering and I was like, "Wow, my body is getting used to this. I can thermoregulate." And I slowly started to figure out how to keep comfortable and keep warm. And of course, your body adapts. But the interesting thing is, if I've had a bad day or I haven't slept well or I've had an injury, I go in the water and it's very difficult for me to thermoregulate. If I've had a great day, I've slept well, I'm feeling strong, I can stay in for a very long time, up to two hours. But if I'm compromised mentally, I can sometimes be cold within 20 minutes. ... I've noticed exactly the same with other people. The cold is a kind of a mirror to how you are feeling mentally.

"The excitement for me has been to slowly uncover the secret lives of many of these cryptic animals," says Craig Foster. "My incredible octopus teacher, she helped me in many ways to uncover many of those lives, because she's in the middle of this food web."
Netflix

On what it's like diving inside the underwater kelp forest

It's truly like being in an underwater forest. ... It's like being in this magical other world that is very different to any world that you might have seen on land, and [there are] animals living in all different levels of the forest. A coral reef is two dimensional in comparison in many ways, and there's tremendous biodiversity and very exotic animals. And because there's so many predators, many of these animals are very, very cryptic. So you can easily dive in a forest ... and not see an animal that's been watching you almost every day.

The excitement for me has been to slowly uncover the secret lives of many of these cryptic animals. My incredible octopus teacher, she helped me in many ways to uncover many of those lives, because she's in the middle of this food web. And to know her, you have to know so many animals that she preys on, and of course her predators as well, and then all the scavengers that come to her den. She's this amazing teacher in many ways for the other lives of the animals in the forest.

On the octopus "armoring" by covering herself in rocks

What I found is that octopus, they've got all sorts of ways of dealing with predators. And of course, you'd have known about the inking, you know about the whole camouflage and everything. But one of the last resorts that they do, if they're in the right kind of environment, they will suddenly, very, very quickly pick up up to 70 shells and stones and sometimes even bits of algae and cover their whole body with them by turning their arms over their head because the head is the very sensitive part of an octopus anatomy. And if a predator bites or interferes with the head, there's often a really big problem. So with the suckers, they pick up all these pieces and then in a very short space of time — in seconds — they cover themselves and they're suddenly armored.

On what octopus suckers feel like on your skin

You'd be surprised how incredibly powerful the suction is, and they are covered in a kind of octopus slime that makes it adhere more strongly, but they are very, very strong. I mean, if you try and pull directly back when that animal is holding you, it's really very, very difficult and you'd have to force it. So you have to gently twist and turn if you need to go up to have a breath of air, because you don't want to pull too hard on that animal. So you have to kind of curl and twist to break that incredibly powerful suction.

On watching the octopus begin to decline

It was obviously difficult. You get close to an animal like this and I was certainly dreading [her death]. But at the same time, I guess in some ways it's better than a human death, because it's quite merciful. It's quite short. ... When she gets to the end of her life, she becomes senescent, senile. So her brain starts to not work so well. So she's not fully aware of what's going on, and that brought some comfort.

On still visiting the octopus' den after her death and feeling her presence

She had a few dens but her main den, where she spent most of the time, I went to visit that den today, this morning. It's a great feeling to go there. I just dive down and kind of silently thank her for this incredible teaching that she's given me.

What happens is once she moves out of the den, it soon fills up completely with sand. So it's basically just a rock edge. But what's so interesting is that other octopuses seem to be able to somehow sense exactly where she's denned and they have made a den in exactly that same place. I've seen this at other sites as well. ... Maybe they [have] some incredible ability to smell, because then they have to excavate and dig the whole den up; there's no sign of it having been there. I'm sure in a few weeks or a month I will find another octopus in exactly that same place.

Lauren Krenzel and Thea Chaloner produced and edited this interview for broadcast. Bridget Bentz, Molly Seavy-Nesper and Beth Novey adapted it for the Web.

Copyright 2020 Fresh Air. To see more, visit Fresh Air.

DAVE DAVIES, HOST:

This is FRESH AIR. I'm Dave Davies, in for Terry Gross. There's a new film which documents an unusual but touching friendship. FRESH AIR producer Sam Briger talked to the filmmaker. I'll let Sam take it from here.

SAM BRIGER, BYLINE: One of the most heartening films of the year is about the relationship between our guest, filmmaker Craig Foster, and an octopus he befriends while diving off the Western Cape of South Africa. Foster had been burned out from years of working on arduous nature films and decided he needed a reset. Craig Foster vowed that he would dive without a wet suit or oxygen tank every day for a year into the chilly waters near where he grew up to explore the kelp forest, an ecosystem teeming with life. It was there that he gained the trust of an octopus who allowed him into its world, where Foster discovered things about its life and his own. Foster's film is called "My Octopus Teacher," and it's available on Netflix. He also has a book about his exploration of the kelp forest called "Sea Change." Foster's received over 60 international awards for his work in documentary films. I spoke to him from his home in Cape Town.

Craig Foster, welcome to FRESH AIR.

CRAIG FOSTER: Thank you, Sam. Glad to be here.

BRIGER: So this journey began when you started diving in the waters of the Western Cape, near where you grew up, every day for a year. What compelled you to do that?

FOSTER: Well, I just, you know, I had been through a very, very busy time. I felt tired, lacking drive. I was burnt out. And my earliest memories, my deepest and most powerful memories were of this incredible coast and diving in what I call my magical childhood forest, the Great African Sea Forest, this underwater forest. So it was a natural place for me to go, just to keep going into that water every day. And as I did that day after day, I slowly started to get my energy back and realized that there was this, you know, whole new way of looking at this underwater forest. And I started to come alive again.

BRIGER: These are not friendly waters. In the movie, you see these huge waves crashing upon the shore rocks. And we see you in the water. And you look like you're being pushed about by these waves. You know, you look pretty vulnerable. What are the perils of diving here?

FOSTER: So you're right. It's called the Cape of Storms for a good reason. They're enormous, enormous waves and some of the biggest surfing waves in the world. And, you know, people are scared of sharks and big animals and that kind of thing, which aren't actually really a danger at all. But the one thing that is very dangerous are these enormous seas. And I have come very close a few times to losing my life and have been sucked into underwater caves and this kind of thing. So if you are dedicated to diving every day especially, you have to be very, very careful and try to read the weather very well, try to read the currents. And then, you know, don't venture into those very dangerous places during those times. There's always some little place you can find to get in which is relatively safe, but it took a while to learn exactly how to do that.

BRIGER: And these are cold waters. It sounds like they can get to 46 degrees Fahrenheit. But you decided to dive without a wetsuit and without an oxygen tank. Why is that?

FOSTER: You know, it's interesting. A lot of people initially said, you know, what - why are you driving without a wetsuit? It's crazy. And over the years, I've taken many people into the water to show them what it's like to skin dive, to free dive without with a minimal equipment. And, Sam, what it does is, first of all, the cold actually changes the chemical nature in your brain. It pushes a whole lot of feel-good chemicals into the brain. So you feel alive. You feel awake. You feel stimulated. But because you can feel that water on your skin, you can feel this slight temperature differences. You feel much closer to nature. You feel more amphibious in a way.

I like to ponder on the amphibious nature of our humanness, and diving in this way with this method brings out that amphibious nature. So there are actually quite a lot of advantages to it. And what it does in the long run is that this cold stress actually puts a certain stress on the immune system that makes it quite a lot stronger. So you get much healthier during that process.

BRIGER: But did it take you a while to acclimate to swimming in those temperatures? How much time would you actually be in the water?

FOSTER: So at first, it took me quite a long time, I have to admit. Other people have seem to have acclimatized much more quickly, people that I've subsequently taken in. So I remember shivering for about a year every day. And then one day, I just stopped shivering. And I was like, wow, my body is getting used to this. I can thermoregulate. And I slowly started to figure out how to keep comfortable and keep warm. And, of course, your body adapts.

But, you know, the interesting thing, Sam, is if I've had a bad day or I haven't slept well or I've had an injury, I go in the water and it's very difficult for me to thermoregulate. If I've had a great day, I've slept well, I'm feeling strong, I can stand for a very long time, up to two hours. But if I'm compromised mentally, I can sometimes be cold within 20 minutes. So it's very interesting. And I've noticed exactly the same with other people. It's - the cold is a kind of a mirror to, how are you feeling mentally?

BRIGER: And what about holding your breath? Like at first, how long could you stay under water, and how were you able to improve that? Was it just by practice that you got better?

FOSTER: Yes, of course. Certainly by just going every day, practicing your breath naturally gets better. And then I sometimes do breathing exercises on land, seeing how long I can hold my breath, that kind of thing. But it's very different. What people don't realize is that if you're filming and you're working under water and you're moving your body, you're using up quite a lot of oxygen. I can't do the classic free diving technique of breathing up on the surface for minutes and relaxing my whole body and just taking one long, incredible deep dive.

I'm working, you know, with these incredible animals in the sea forest. So I need to be going up and down a lot because I need to be with them. So I've had to get good at having just one or two breaths at the surface and going down for as long as I can, then one or two breaths of the surface and going down long as long as I can. So it's a different technique to these long one-breath free divers you see doing these incredible depths.

BRIGER: So during these dives, you discover this particularly beautiful kelp forest. What makes a kelp forest special? Is it sort of like a coral reef in its diversity of sea life?

FOSTER: It's completely different to a coral reef. So if you can imagine, it's, you know, it's truly like being in an underwater forest. The holdfasts are like the roots that are stuck to the rock. And they had long stipes, which are like the stems of the tree. And then on the top are the leaves, the blade and the leaves of the tree that float on the top. And the stipe is filled with gas, so it floats. And the light, you know, sprinkles through the top of these leaves. And you get these incredible shafts of light. It's like being in this magic whole other world that is very different to any world that you might have seen on land and the animals living in all different levels of the forests.

A coral reef is two dimensional in comparison in many ways, and there's tremendous biodiversity and very exotic animals. And because there's so many predators, many of these animals are very, very cryptic. So you can easily dive in a forest, which happened to me for years, and not see an animal that's been watching you almost every day. And the excitement, for me, has been to slowly uncover the secret lives of many of these cryptic animals.

And my incredible octopus teacher, she helped me in many ways to uncover many of those lives because she's in the middle of this food web. And to know her, you have to know so many animals that she preys on and of course, her predators as well and then all the scavengers that come to her den. And she's this amazing teacher in many ways for the other lives of the animals in the forest.

BRIGER: Well, let's talk about the octopus. So one day you're diving in the kelp forest and you see this strange collection, like, it's like a ball of shells and rocks. And you realize there's an octopus in there 'cause the octopus swims away at some point, and it's been holding all the shells and rocks against its body covering itself. And it sounds like this behavior had not been documented before. What have you learned about this behavior?

FOSTER: Yes, you're absolutely right, I mean, I call this behavior armoring. And what I've learned is that - I mean, this took quite a while to figure out. And, you know, I'm lucky enough also to work with amazing scientists who help me figure out a lot of these mysteries that I observe in the forest, and some of them dive with me - my professor Charles Griffiths, who's this, you know, wonderful mentor - Dr. Jannes Landschoff, he's a wonderful young marine biologist who dives with me a lot - and then professor Jennifer Mather, who's a octopus specialist.

So - and I go and film these things, and then I discuss things with these wonderful scientists, and we try and figure it all out. And what I found is that octopus, you know, they've got all sorts of ways of dealing with predators. And of course, you'd have known about the inking. You'd - you know, you know about the whole camouflage and everything.

But one of the last resorts that they do, if they're in the right kind of environment, they will suddenly very, very quickly pick up up to 70 shells and stones and sometimes even bits of algae and cover their whole body with them by turning their arms over their head. Because the head is the very sensitive part of an octopus's anatomy. And if a predator bites or interferes with the head, there's often a really big problem.

So with the suckers, they pick up all these pieces, and then in a very short space of time, in the seconds, they cover themselves and they're suddenly armored. And this is a - you know, in evolutionary perspective, this animal has discarded its shell to become more of a liquid creature, so there's a lot of advantages to being a liquid creature. And then, in this incredible way, has figured out a way to quickly create this temporary shell, hard shell that, well, can deter a predator.

BRIGER: Yeah, it's amazing. And I think, you know, during your time in the kelp forest, you're just fascinated by this creature. And so you start visiting it every day, and you actually gain its trust. And it becomes comfortable following you around, and it lets you follow it around. And it would even attach to you and swim with you. Had you ever had an interaction like this with a wild creature before?

FOSTER: Not anywhere at this level because I've been diving for years. I've been diving since I was 3 years old. I'm now 52. And in the last nine years, I've dived every single day as a commitment to understanding the ocean. So I have had fascinating encounters with various animals, animals that have decided to come and make contact with me. But it's mostly fleeting. You know, it happens just on one occasion, on one day. And it's kind of mysterious, and it's interesting.

But this was different in that, you know, this was over a long period of time that this trust and this physical contact built up. Sometimes when she'd eaten or when she was - you know, they're quite moody. Sometimes she didn't want to have contact. So it wasn't like it was happening absolutely every day, but certainly had many extraordinary experiences with her many, many times. I couldn't, you know, film them as well. So, you know, the film is just a slice, really, of the experience of being with this incredible creature and learning from her.

BRIGER: Well, let's take a short break here. I'm speaking with Craig Foster about his film "My Octopus Teacher," which is available to watch on Netflix. More after break. This is FRESH AIR.

(SOUNDBITE OF LOOP 2.4.3'S "ZODIAC DUST")

BRIGER: This is FRESH AIR. If you're just joining us, our guest is Craig Foster. His film "My Octopus Teacher" is about the trust he gained of an octopus while diving every day for a year into the kelp forest off the Western Cape of South Africa. You can find the movie on Netflix.

So you're fascinated by this octopus and you decide that you're going to go visit it every day and observe it. And at one point, the octopus actually reaches out and touches you. What did that moment feel like?

FOSTER: You know, that's obviously a special moment when that animal decides to make that first contact. There's something special when that happens for sure. And, you know, other octopuses have done that to me as well, but it was somehow different with her. It's impossible to explain. But you must realize, Sam, she's still holding on with all her arms. It's just that one arm that she's sending out. The real moment when I was, like, just completely blown away was when she came out the den right in front of me, and then there's no arms holding back. That's when I realized this animal trusts me. She no longer sees me as a threat. And her fear changes to curiosity. That's the big moment.

The really rare and special thing is when the trust forms, and that is a totally different scenario. When that animal comes out, and there's no - its whole body is vulnerable. And she goes about hunting and doing her incredible behaviors. That's when the real excitement comes. And you think, oh, my goodness, I'm being let into the secret world of this wild animal. And that's when you feel on fire.

BRIGER: So when the octopus touches you, what do the suckers feel like?

FOSTER: You'd be surprised how incredibly powerful the suction is. And they are covered in a kind of octopus slime that makes it even adhere more strongly. But they are very, very strong. I mean, if you try and pull directly back when that animal is holding you, it's really very, very difficult. And you'd have to force it. So you have to gently twist and turn if you need to go up to have a breath of air because you don't want to pull too hard on that animal. So you have to kind of curl and twist to break that incredibly powerful suction.

BRIGER: With a creature like this that seems so foreign to us, I think it's really confusing to understand why it's doing what it's doing. But it seems like the octopus was as interested in you as you were in it. Why do you think that's the case?

FOSTER: So as you say, Sam, it's very difficult to know what a cephalopod, an octopus, is thinking. And I don't pretend to know what she was thinking. But they are very curious by nature. So they oscillate between fear and curiosity. And especially in this Great African Sea Forest here on the tip of Africa where there's so many predators, octopuses tend to go more on the fear side of things. So most of the octopuses I've encountered are doing some activity or doing some behavior. As soon as they see me and my presence is in the water, they will discontinue and try and hide away and get away. And if I - if they're at their den, they'll just go maybe deep into the den.

So it's only after a while this animal figured out, OK, this person - and remember, they can recognize individual people, that's been proved - realize I'm not a threat. And then, you know, the whole game changes because that fear is overcome by that incredible curiosity. And, you know, what is this creature? How does this creature feel? And remember, the suckers can taste as well. So how does the flesh - how does it - what it tastes like. And it was fascinating to see, you know, how she sometimes used me in her hunting strategy. So she'd use my body sometimes to corral the prey, that kind of thing. So maybe I was quite useful in that way sometimes.

BRIGER: (Laughter) Yeah.

FOSTER: It's not easy to know what she's thinking.

BRIGER: Well, I have a question about that. Is it easy, or is it a trap to start anthropomorphizing a creature like this when you're trying to understand its behavior?

FOSTER: I think you have to be very careful of that because she's - you know, she's 200 million years away from us on the evolutionary scale. So in some ways, she has this very ancient, ancient mind, but her neural makeup is, in some ways, similar to ours. So there is a possibility that she could feel certain emotions. But how those are interpreted - and also, what's very interesting, Sam, is that two-thirds of her cognition is outside of her brain, in her arms. And so her arms have this external cognition.

And, you know, it's a hard fast to get our thoughts around how that all works. So you're dealing with, you know, a very different creature in many ways. But perhaps the underlying nature of cognition is not that dissimilar. That's also in the back of one's mind. So you - it's mysterious, and that's what makes it so interesting. And that's why I will study these animals for the rest of my life. And I only know a tiny bit of how they work.

BRIGER: We need to take another short break here. We're speaking with Craig Foster about his film, "My Octopus Teacher." You can watch it on Netflix. We'll be back after a short break. This is FRESH AIR.

(SOUNDBITE OF CLEVELAND ORCHESTRA, CLEVELAND ORCHESTRA CHORUS, GARETH MORRELL AND PIERRE BOULEZ'S "NOTURNES: III. SIRENES")

BRIGER: This is FRESH AIR. I'm Sam Briger, sitting in for Terry Gross. Let's get back to my interview with filmmaker Craig Foster about his new movie, "My Octopus Teacher." While Foster was diving in the kelp forest off the coast of South Africa, he gained the trust of a wild octopus that allowed him to visit it every day and learn about its behavior. Foster was present for about 80% of the octopus' life. "My Octopus Teacher" is available to watch on Netflix.

So I'd like to talk more about these remarkable creatures. You know, what really amazes me is their skin. They have this almost instantaneous ability to change their color as camouflage. So can you tell us a little bit about how that works? Like, how are they sensing the colors around them? Because I think I read that octopus are color blind.

FOSTER: Yeah. You know, you've done your research. That's the strange thing is, how on earth can an animal that's color blind match its color so perfectly and camouflage with its background? I mean, it's just like, you know, what on earth is going on there? And as far as I can understand, we don't fully understand how that's possible. But there are some interesting clues. And I think cuttlefish provide us - you know, cuttlefish are closely related to octopus.

And I think if I'm - speak under correction - but they can actually hack color by looking on the edges by having this chromatic shift in their eyes. They've got these strange shaped eyes. And they can actually see color, even though they're color blind in this chromatic shift. There are also opsins in their skin that can detect some form of light or color. But it is quite an incredible thing that an animal that is, you know, essentially seeing in black and white can camouflage in color in such an extraordinary way. And they've got various - the main thing they use are chromatophores, which are like ink sacs that they can shrink or expand to change the color. And then they've got various layers underneath that of different ways that they can make themselves look - I think they're called iridophores - almost translucent and sparkly.

So they've got these layers of - but what I noticed was something that was very interesting is that if an animal was on a surface and it was battling to match the color of that surface, what I found so fascinating was instead of trying to get something that it couldn't quite get right, it would find another object, maybe another animal, another mollusk or another plant on that surface and rather mimic that. So the octopus looked like just another abalone or just another piece of algae on the substrate. You with me?

So you can - that's extraordinary intelligence. So I'm battling. I'm battling. I'm struggling to match my surface. OK. There's an object over there. I'm going to match that and pretend that I'm a piece of algae or an impenetrable abalone, and then the predator won't see me. I mean, that's incredible intelligence. And these are the kind of things I noticed over the time with her.

BRIGER: The skin of the octopus also seems to be changing all the time, like it's smooth or it looks beaded. They can span their arms or contract them. They sometimes will make little horns on the top of its head. Do we understand what that's all about?

FOSTER: Yes. So there are muscles all over the octopus, and it can pull up its skin into these incredible shapes with these little muscles, and that's why I can grow the horns on the head to look fierce. Or it can - if it's on a surface that is very rugged, it can pull its skin up into looking very pretty to match that surface. Often a smooth surface can make its skin completely smooth. So it's got tremendous - and it can, as you say, telescope its arm to I think at least twice the length of the normal arm.

So it's literally a liquid creature that can squeeze through the tiniest, tiniest gaps. And you can imagine in a - as when you're being chased, like I witnessed, you know, a crab hunt. What does that crab when you're being chased by a liquid animal that can just literally squeeze itself through any tiny little crack and get hold of you? It's a very - it's frightening.

BRIGER: Yeah. You clearly felt very close to the octopus. How did you decide whether or not you would intercede in its life if it was in danger?

FOSTER: When you are getting to know all the animals in the Great African Sea Forest, you're getting to know all of her prey species and that she can kill and eat over 50 different types of prey. You're also getting to know her predators. And her main predator in this area I was were these pajama sharks, but, of course, you get to know these animals very well. You watch the adults lay their eggs. You watch those eggs and that baby shark developing in there. And then you see a predator just before that shark's about to hatch eat that tiny shark out of the egg.

So you get close not only to your wonderful octopus teacher, but you get close to these beautiful sharks, and you see how difficult their lives are. And you get to see how they their struggle to survive. And they're a much longer-lived animal. So it's harder for them. So you develop this empathy for the whole living ecosystem. And you - it's very hard for you then to come in and start interfering with something that's kept its balance for millions of years. It just doesn't seem right.

BRIGER: There's this moment that's really hard to watch in the film where a pajama shark actually attacks the octopus and rips off one of her arms. And fortunately, the octopus recovers. But can you tell us what you were going through when that happened?

FOSTER: Sure. I mean, it's just - in a - it must realize it's happening so fast. And it's swirling ocean. And, you know, I was obviously just terrified for her. She went right deep under a rock. And I thought that she'd escaped and was fine. And I was absolutely shocked when that pyjama shark was able to almost burrow its, you know, pointed head right in there, grab hold of her arm, and then just do this terrifying death roll, like a crocodile death roll, and twist and take her arm off. And it was a shock and, yeah, a most unpleasant experience.

BRIGER: Does it expend a lot of energy for an octopus to regrow an arm like that?

FOSTER: It's a fair amount of energy to regrow. But what's amazing is that about a third of all the octopus in this great African sea forest have missing limbs. So it's something that happens a lot and that it's - you know, they are very capable of regrowing those limbs. And they can survive, actually, I think quite easily. It's if they get bitten in the head, that's when the problems - you know, then it's much more serious.

BRIGER: Let's take another short break here. My guest is Craig Foster. His film, "My Octopus Teacher," can be seen on Netflix. More shortly. This is FRESH AIR.

(SOUNDBITE OF GAIA WILMER OCTET'S "MIGRATIONS")

BRIGER: This is FRESH AIR. If you're just joining us, we're talking with filmmaker Craig Foster about his movie, "My Octopus Teacher," which you can find on Netflix.

So, you know, the common octopus has a pretty short life span of about a year. And you had - you know, you figured out you'd been spending a lot of time with this octopus and clearly her lifespan was coming to an end. Did you start to feel ambivalent about your trips to the ocean during those last days? Like, were you looking forward to seeing her but also dreading the end?

FOSTER: Yeah. It was obviously difficult. You know, you get close to an animal like this, and I was certainly dreading that. But at the same time, I mean, I guess in some ways it's better than a human death because it's quite merciful. It's quite short. And also what happens when she gets to the end of her life, she becomes senescent - senile, so her brain starts to not work so well. So she's not fully aware of what's going on, and that brought some comfort.

BRIGER: So we see the octopus mate, and a male octopus comes along. And it's at first just sitting near her, and then it looks like one of its arms is extending out to her. What's mating like for an octopus? It looked pretty transactional.

FOSTER: Yes. I mean, it can be very dangerous sometimes, you know, especially if the female is bigger. She can even kill the male after mating. So sometimes he's very cautious. And that's why he's, like, extending the arm right out. Like, there's this tiny little penis on the end of the arm. And so it's - yeah. They're very anti-social animals. So it's not some great love affair, that's for sure.

BRIGER: (Laughter) And does this process signal the end of the life cycle for both the male and the female?

FOSTER: Correct. So the male also starts to deteriorate quite quickly after the mating. It's called - I think the word is semelparous. And many animals, especially insects, have the same process.

BRIGER: So the octopus hatches her babies, and at this point, she's sort of been holding on to her life energy to sort of get to that point, and then she's sort of at the end of her life. And her energy is gone, and her body washes out of her den. And there's this incredibly beautiful but sad image that you have of her laying on the sea floor. And her eyes are closed, and she's gotten really pale, so she can no longer sort of change the color of her skin. And, like, her body's swaying a little bit with the movement of the water. It's an incredibly moving shot. I was just wondering what you felt taking that shot.

FOSTER: Yeah. I mean, it's an - it's most difficult - very, very difficult. And it's hard to sort of express it without getting a bit emotional, so I almost try to not to think of that too much because it makes me feel sad - so very difficult - yeah, very difficult.

BRIGER: In the movie, you say that you still visit her den after her death and you sort of float above it and feel her presence. Do you still do that? Do you visit her den?

FOSTER: Funny enough, Sam, I went to her - you know, she had a few dens, but her main den where she spent the most of the time, I went to visit that den today this morning. Yeah, it's just a great feeling, you know, to go there. And, you know, I just dive down and kind of silently thank her for this incredible teaching that she's given me. And what's so interesting is that, you know, I've seen - there was nothing - what happens is once she moves out of the den, it soon fills up completely with sand. So it's basically just a rock edge.

But what's so interesting is that other octopuses seem to be able to somehow sense exactly where she's denned stand and they have made a den in exactly that same place. And I've seen this at other den sites as well. So there's something - maybe they can smell - there's some incredible ability to smell because then they have to, of course, excavate and dig the whole den out. There's no sign of it having been there. And so I'm sure in a few weeks or a month, I will find another octopus in that same - exactly that same place. And it's not, you know, 20 or 30 centimeters away. It's in the same place.

BRIGER: So, you know, you're trying to get protected status for the sea forests along the Western Cape. What are some of the threats to this ecosystem?

FOSTER: There are multiple threats to the ecosystem. Industrial fishing, I think, is a massive threat as is, and it's a threat to the whole ocean. We have pollution as, you know, a serious threat, especially rivers being polluted and chemicals running into the sea, which, you know, is, again, a worldwide problem. We have a fairly serious poaching problem, especially with abalone and to some degree with rock lobster and overfishing of especially reef fish. Many of them are endangered, if not almost at the end of their lives - of their species. So they are really in a development - coastal development. People wanting to put up hotels and big complexes right on the seashore is, you know, is really a death knell for the environment. So there are multiple threats, even the threat of mining the ocean bed. You know, so there are unfortunately multiple threats.

And what we try to do is to get this - we're calling it the Great African Sea Forest - have it get to be known worldwide, much like the Amazon or the Serengeti or the Great Barrier Reef, the Great African Sea Forest, because it is one of the greatest ecosystems on this planet. And it's still, to a large degree, intact. The habitat's intact. Many of the species have been knocked right down. We desperately need to regenerate many of those species. But this is - there's hope here. So what we are trying to do is to show just how extraordinary this living system is. And it is absolutely vital for the well-being of every human on Earth. And we actually breathe because of it, especially because of the ocean. So we all need to come together and really try to figure out a way of not just being sustainable but actually regenerate these wild systems because they are the immune systems of our planet. The biodiversity is the thing that keeps the world healthy and that keeps humans healthy. And as soon as you get that into your head, then you would want to do everything to keep that biodiversity and all those animal species in place.

BRIGER: Are you still diving there every day?

FOSTER: Oh, yes, yes. I was in today and I'll be in tomorrow. You know, even if I have a long working day, I'll try and get up very, very early and get in. It's just something that I really - makes me feel good.

BRIGER: Craig Foster, thanks so much for coming on FRESH AIR.

FOSTER: It's been a great pleasure, Sam, speaking to you, and I really appreciate it.

DAVIES: Craig Foster's film is "My Octopus Teacher." It can be seen on Netflix. He spoke with FRESH AIR producer Sam Briger. Coming up, David Bianculli reviews Aaron Sorkin's newest drama, "The Trial Of The Chicago 7." This is FRESH AIR.

(SOUNDBITE OF TANTSUI'S "BEAUTIFUL DAY") Transcript provided by NPR, Copyright NPR.