#bottlenose dolphin

[marine-gifs]

A pair of bottlenose dolphin hunting. Filmed in Denmark. From Wild Skagerrak (2016).

[critter-creature-or-beast]

This is a...

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Voting ended onApr 8

By Sergio Martínez, CC-BY-NC

Originally voted Creature on December 13, 2023

[local-hellhound-steals-spaghetti]

do you really not find it weird to keep animals confined that have more complex brain structures than we do? I'm not generally anti zoo but keeping cetaceans, esp orcas, just icks me out. breeding calves is not an indicator for happyness, unhappy, unhealthy people have kids all the time (child protective services exist for a reason), so do animals eg. puppy mills

Hey anon, there's actually no solid body of evidence to support that cetacean brain structure complexity is related to hyperintelligence. In fact, the person who makes this claim has yet to link brain structure to behaviour observed.

Just because a brain is "bigger" doesn't mean it functions in the same way. Humans live in a two-dimensional environment, with our primary sense being vision. We have our feet on the ground and move left, right, forward or backwards.

Whales live in three dimensional environments in water. They can surface and dive the way we only wish we could. Our umwelt in comparison to each other is chalk and cheese. The only thing we can relate to is being a social animal with complex communcation abilities and the capacity to learn and pass on knowledge to each other and the next generation.

Looking a dead orca brains is all well and good, but without relating structure to function for the animal when they're alive... well you can pretty much say whatever you want.

Take Marino et. al (2020), a paper uncritically spread around by media outlets despite being heavily criticised for it's obvious bias, misinformation and conclusions drawn from little to no data.

They discuss Marino's own data on brain structure and then use unrelated metrics like calf mortality (which is very high in wild populations) to claim that captivity is "harmful" and causes chronic stress. No welfare data, no veterinary records or behavioural analysis. That is just bad science.

Lori Marino likes to make inferences about the brain as a neuroscientist but there's very little substance in what she actually says, especially in relation to human care and what is observed in those populations. For example Marino et. al (2020) infers "greater cognitive complexity increases the need for a complex environment and experiences", without elaborating further.

Their conclusion is always that this "complex environment" is unattainable in a managed care environment and only possible in a sea sanctuary (which Marino profits from the donations towards). Conflict of interests aside, how is that helpful in understanding how brain structure is related to ability to live in human care?

Complex cognition = adaptability and ability to learn. It's very likely the reason why certain species are able to thrive in certain environments than others. And the idea of a "complex environment" falls somewhat short when you consider that pelagic orcas live in deep ocean, which is essentially a biological and visual desert of endless blue.

The complexity comes from their social relationships and their ability to live in social groups - which is also very possible in appropriate managed care. Especially when you have healthy breeding populations, which create natural female and calf nursery groups, which is where a lot of social learning happens. And depriving the animals of these natural groupings is likely extremely detrimental for long term welfare.

You can be "icked out" if you want, but orcas are not humans with fins.

Orcas are separated from humans by hundreds of thousands of years of evolution, living with environmental pressures we can barely even concieve of. Living in a world of sound that thrive in complex social groups - and btw the idea that cetaceans can't echolocate in tanks is a myth, they are more than capable of modulating their clicks and using echolocation when needed (ask any researcher studying cetacean communication in tank environments)

Cetaceans do not breed successfully under high stress - that is just the reality. Humans are very different and as someone who never wants to get pregnant, I understand the want to project onto whales this horror of being "forced" into pregnancy. But cetaceans are very socio-sexual animals and it is very normal and natural for them to want to reproduce.

And some female orcas are definitely better mothers than others and more successful, which is why you see female orcas like Katina with so many calves to her name. It's hard to overstate how enriching calves are for a lot of cetacean species.

Like when I saw the female bottlenose dolphins I worked with all pitching in to help babysit the new calf so the mum could have a rest... that was such a beautiful example of how social bonds were reaffirmed through a new calf. This was especially for the females, who were stroking each other with their pectoral fins and surface resting side by side, always touching each other and vocalising.

Some females will even start producing milk to help nurse the calf for the mother. Even when the calf is weaned they'd all be playing with the new calf, showing them how to play with the fish in the lagoon or find seaweed to throw around. And yet people will say that breeding in these environments is "unnatural"? I couldn't disagree more.

I love this video from Dolphin Quest with Dr. Holley Muraco (who I had the privillege of meeting and working with during my internship), who studies cetacean reproduction and who sees first hand how important it is.

Anyway

TL;DR Orca brains are not human brains, therefore it is not realistic to expect orcas to think and experience the world like humans. Brain size and complexity should be linked to function, rather than vague ideas of "hyperintelligence" and projected human concepts. Cetaceans do not breed successfully in poor conditions and are, again, not humans. Reproduction has been shown to be very beneficial for health and welfare, especially for female social groups. More research would have to be done to see if similar health benefits apply to killer whales.

[aquatark]

Dolphin Partner Icons

Endless Ocean: Blue World, Nintendo Wii

what did you name them all?

[namu-the-orca]

Here it finally is, the full cetacean eye colour info sheet! A long time coming, and an even longer time in the making. I hope that all you cetacean eye curious people will find this one as fascinating as the killer whale eye colour post. It’s a wild world out there! 

[commersons]

[sugargrim3]

Haruka was an estimated 15-20 year old female Pacific bottlenose dolphin who was captured on October 28th of 2006 and placed at Taiji Whale Museum, she would later on pass from multiple organ failure on April 4th of 2013.

This dolphin was considered very special due to the fact that she was born with two vestigial hind limbs that were about 15cm on either side of her genital slit, she was given the name Haruka through a visitor poll, as the name means "of the past" as this was a characteristic of the ancestors of modern cetaceans.

Haruka was seen as a big opportunity to research and learn about the evolution of cetaceans, there were also attempts to have her mate and to produce offspring but nothing ever came of it.

[todropscience]

MICROPLASTICS FOUND IN THE EXHALED BREATH OF DOLPHINS

Microplastic is a ubiquitous environmental contaminant, widespread across terrestrial and marine environments. In the environment, microparticles have been documented in a variety of fauna. Human epidemiological studies have found relationships between inhaled microplastics and oxidative stress, as well as inflammation.

Recent research has uncovered something quite striking: bottlenose dolphins in Florida and Louisiana are exhaling microplastic fibers. While plastic pollution has been well-documented in marine environments, this new study adds inhalation to the growing list of exposure routes for these animals. Bottlenose dolphins were found to be exhaling microplastics similar in chemical composition to those found in human lungs. Their exposure to microplastics might reveal broader environmental risks, especially for cetaceans health.

Breath samples were collected from wild bottlenose dolphins during health assessments conducted by scientists in collaboration with several organizations, including the Brookfield Zoo in Chicago and the Oceanogràfic Foundation. The researchers used a Petri dish or a custom spirometer to capture the dolphins' exhaled breath and, in the laboratory, analyzed the samples under a microscope for small plastic particles characterized by their smooth surface, bright colors, or fibrous shapes.

- A microplastic from a bottlenose dolphin's breath, nearly 14 times smaller than a human hair. Photo by Dziobak/College of Charleston.

The study found microplastics in dolphins from both urban and rural estuaries, demonstrating that even less-populated areas are not immune to plastic contamination. The key takeaway is that plastic pollution is a widespread issue, with effects that may be more far-reaching than initially thought. While the impacts on dolphins' lung health remain unknown, this research underscores the need to investigate how microplastic inhalation could affect marine life and humans alike. Reducing reliance on plastic is a crucial step toward addressing this growing problem.

Main photograph: Todd Speakman/National Marine Mammal Foundation.

Reference (Open access):  Dziobak et al. 2024. First evidence of microplastic inhalation among free-ranging small cetaceans. PLoS ONE