Ocean Animals and the Mirror Self Recognition Test

dolphin mirror test, mirror self recognition test, self aware animals

Dolphin reacts to own image in mirror

With recent news that the cleaner wrasse might have mirror self-recognition (MSR), I thought I’d write about the ocean animals that have MSR. Bottlenose dolphins and killer whales have MSR for certain. Possible mirror self-recognition ocean animals include manta rays and cleaner wrasses. Ocean animal that failed the mirror self-recognition test is the octopus.

So what is self-recognition? With a mirror, self-aware animals such as chimpanzees and bottlenose dolphins recognize themselves and don’t react as if the image is another animal of the same species. Some animals that don’t have self-recognition react to their image in a mirror with aggression or other more positive social behaviors.

The mirror self-recognition test is when a human researcher places a mark somewhere conspicuous on a captive animal. With human babies, they place a paint mark on their foreheads. Starting at 18 months, human babies investigate the mark when they see themselves in a mirror.

Then the researchers place the test animal in front of a mirror and judge from their actions (usually curiosity) if they recognize themselves or not. Here are some examples from the ocean:

Bottlenose dolphins in captivity react to a mirror image by “opening their mouths, sticking out their tongues and showing novel behaviors.” When marked, they investigate the mark on their bodies by moving the marked area towards the mirror.

Killer whales in captivity were shown themselves unmarked in a mirror. Then they were marked. The whales behaved like they expected their appearance to be altered. This showed that they have self-recognition.

Manta rays possibly show mirror self-recognition. When captive manta rays had a mirror placed in their tank, they blew bubbles, which they normally don’t do. They also appeared to investigate their image in the mirror by turning their belly towards the mirror and swimming by the mirror repeatedly.

Cleaner wrasses were injected with a mark, which is how scientists mark fish in their studies. When their throats were marked and a mirror placed in their tank, the cleaner wrasses would rub their throats against the tank. Throat rubbing is not behavior seen in wild cleaner wrasses. When the mirror wasn’t in the tank, the wrasses didn’t rub. So seeing the mark in the mirror caused the throat rubbing and hence cleaner wrasses possibly have self-recognition.

As a side note, the inventor of the mirror self-recognition test, Gordon Gallup of the State University of New York, doesn’t think cleaner wrasses have self-recognition and that the study was flawed. What do you think?

Octopuses haven’t passed the mirror test, but in studies they do orient themselves towards the mirror. Octopuses rely on their sense of touch and don’t rely on vision as much as mammals do, so it makes sense they don’t show mirror self-recognition.

On a personal note, I have dived with manta rays off the coast of Hawaii. I looked them in the eye and saw straight into their soul. It was no different than looking into a dog or cat’s eyes. I knew something was going on behind them. I don’t doubt that manta rays are thinking beings and that they may be self-aware.

Websites consulted:
List of Animals That Have Passed the Mirror Test
Article, “Is this Fish Self-Aware?”

Posted in Elasmobranchs, Moby the Manta Ray | Tagged , , , , | Leave a comment

10 Fabulous Facts About the Sea Cucumber

sea cucumber facts, sea cucumber species, sea cucumber

Chocolate Chip Sea Cucumber photo by: NOAA National Ocean Service

1. Sea cucumbers are not a vegetable, but an invertebrate (animal without a backbone). They are like a squishy leather-like terrestrial cucumber with a mouth on one end and an anus on the other. They breathe through their anus.

2. There are 1,200 known species of sea cucumbers. Sea cucumbers come in many colors, including orange, red, and brown.

3. Sea cucumbers are echinoderms and are related to sea urchins and sea stars.

4. They are abundant on coral reefs, one per square meter on un-fished reefs. Below 15,000 feet (the deep sea), they make up 90 percent of life on the seafloor.

5. Small animals sometimes take refuge in the sea cucumber’s rectum!

6. They average 3-12 inches long, but can be as small as 0.75 inches and as long as 6.5 feet.

7. Sea cucumbers are nocturnal and play an important role on a coral reef. *see more below

8. Sea cucumbers have 2 lines of defense. They can shoot out white sticky threads that tangle up any predator. They also can expel their internal organs, which are then regenerated.

9. The larvae (“baby” sea cucumbers) of sea cucumbers are planktonic and float in the ocean currents. The adults are benthic, which means they live on the seafloor.

10. A sea cucumber can live 5-10 years (if it doesn’t get eaten or fished out as an Asian delicacy).

*Sea cucumbers are scavengers and ingest sand to eat whatever’s “stuck” to it, much like an earthworm ingesting dirt for food. The sand moves through the sea cucumber’s acidic digestive tract. The acid dissolves calcium carbonate from the sand and it goes into the surrounding seawater. Corals use that calcium carbonate to build their skeletons. Calcium carbonate is alkaline (like an antacid) and can buffer acidic seawater. Scientists are studying if sea cucumbers can help mitigate the negative effects of ocean acidification due to climate change.

Facts from:
7 Facts You Didn’t Know About Sea Cucumbers
National Geographic page on Sea Cucumbers
National Wildlife Federation’s Page on Sea Cucumbers

Posted in 10 facts, Other Marine Animals | Tagged , , | Leave a comment

What Is Bioluminescence and Why Do So Many Deep-Sea Animals Have It?

bioluminescence, bioluminescent ocean waves, bioluminescent waves, bioluminescent plankton

Bioluminescent ocean waves Photo credit: Phil Gibbs on Visualhunt.com / CC BY-NC-ND

What is bioluminescence?


Bio = biological, or life, Lumen = light (unit)
Bioluminescence is the biochemical emission of light by living organisms such as deep-sea fishes. It produces the “glow-in-the-dark” look of certain animals such as fireflies and the “fireworks” show when plankton are disturbed in the ocean(see photo of bioluminescent ocean waves).

What percentage of animals in the deep-sea are bioluminescent?


90% of animals in the deep-sea (below 1,640 feet or 500 meters) are bioluminescent (according to NOAA [National Oceanic and Atmospheric Administration]).

How do animals and plants produce bioluminescence?


Two chemicals are mixed together with oxygen and the reaction produces light. The chemicals are luciferin and luciferase and together they produce oxyluciferan.

Bioluminescence is made up of what colors?


Mainly blue-green as red is absorbed the further you go down in the ocean. There are species that emit infrared and red light and one group of organisms that produce yellow light.
from Causes of Color website

What kinds of ocean animals are bioluminescent?


Bioluminescent ocean organisms include bacteria, jellyfish, starfish, clams, worms, crustaceans, squid, fish, sharks and more to be discovered! (list according to NOAA)

Why are animals bioluminescent?


Animals are bioluminescent for protection as the light will scare some predators away. The vampire squid has bioluminescent mucus that they eject (like ink) towards predators. Animals can use bioluminescence to find mates (which is hard when in the dark, deep sea with no other light). They also can use it to find food (like Dory in Finding Nemo being drawn to the anglerfish lure. Fortunately Dory wasn’t eaten!). Also it can be used in communication, and for illumination.

What questions do you have about bioluminescence? Leave a comment below.

Posted in Fish, Other Marine Animals | Tagged , , | Leave a comment

10 Fun Facts About the Opah Fish, or Moonfish

Opah fish, Moonfish, opah fish facts, opah fun facts

Opah fish or Moonfish photo by: NOAA Fisheries

1. The opah, or moonfish, is a fully warm-blooded, deep-diving flat and round fish.

2. The opah has a silvery gray body, red fins and mouth, and white spots all over.

3. Opah average 100 pounds (but can weigh up to 200 pounds) and is the size of an automobile tire-about 3 feet in diameter-but oval shaped.

4. Scientists have discovered recently through DNA testing that there are 5 distinct species of opah.

5. Opah eat fish, krill and squid.

6. Opah dive to depths of 165-1300 feet (50-400 meters).

7. Opah swim using their pectoral (side) fins and swim quickly like tuna.

8. Predators of opah include humans and large sharks such as great white sharks and mako sharks.

9. Scientists have tagged opah and found that they migrate thousands of kilometers.

10. Opah are caught as by-catch—by accident—by the tuna and swordfish fisheries. Off the United States, 30,000 opah were caught by the Hawaiian longline fishery in 2015 and the fishery is worth 3.2 million US dollars.

Articles used:
Opah, the first warm blooded fish identified: 7 facts you should know about it

Sleuthing Leads to New Findings About Peculiar Ocean Fish

Opah on animalspot.net

Meet the Comical Opah, the Only Truly Warm-Blooded Fish

Posted in 10 facts, Fish | Tagged , | Leave a comment

Interview With Dr. Deni Ramirez Macias, Whale Shark Researcher

Dr. Deni Ramirez Macias and a Whale Shark

Dr. Deni Ramirez Macias and a Whale Shark


Dr. Deni Ramirez Macias is a whale shark researcher based out of the Gulf of California (Sea of Cortez), Mexico. She is the director of Whale Shark Mexico (Tiburon Ballena Mexico). She started the whale shark research program in 2003 (but has been studying them since 2001). The goals of Whale Shark Mexico are research, sustainable management and environmental education.

I recently went on an expedition and met Dr. Deni Ramirez Macias. This is a paraphrased interview with her:

Cherilyn Jose (interviewer): Where did you get your doctorate degree from and what was your thesis?

Dr. Deni Ramirez Macias: I got my doctoral degree from the University of La Paz. My thesis was on the population genetics of the Gulf of California whale sharks. I found that the whale sharks return to the same area year after year. We re-sighted the whale sharks using photo identification.

CJ: How did you become interested in whale sharks? What was your first encounter with whale sharks like?

DRM: I saw dolphins and rays growing up. During my first close encounter with a whale shark, I found them to be beautiful and charismatic. I was curious about them and wanted to know more.

CJ: How much time do you spend in the field?

DRM: I spend 50% field/50% lab and administrative work. Approximately four times a month I see whale sharks in the field, and I have other researchers that go out three to four times a week.

CJ: Why should we save the whale sharks?

DRM: We should save whale sharks for the ethics of it–life will continue without us and we have to do something (before that happens). Saving whale shark habitat saves other species such as manta rays, mobula rays, and whales—it helps the ocean in general.

CJ: What are some threats to whale sharks?

DRM: Microplastics accumulate in whale sharks, not just in the adults but in the juveniles too. The same goes for heavy metals (and other pollutants). To help I use biodegradable pesticides to fumigate.

CJ: What are some future objectives of Whale Shark Mexico?

DRM: I will collaborate with other researchers in places such as Latin America. I will train locals to help sight and track whale sharks.

Note: Deni and her assistant, Maritza Cruz Castillo, are attempting to ultrasound one of the pregnant female whale sharks that frequent the Gulf of California. Stay tuned for updates!

I will also have posts on the 10 day expedition I took recently to the Gulf of California, with Panterra Expeditions and the Shark Research Institute, when I had a whale shark named after me ☺!

Posted in Fish, Interviews, People and the Ocean | Tagged , | Leave a comment