Can cetaceans breath through their mouths?

[rachelbean]

Yes, but you wouldn't need to if you had a hole on top of your head

[Animavore]

It's a much better design than us humans have. Can't choke to death on food that way!

This needs elaboration if anyone nose (SWIDT?).

Surely because we share a common ancestor the back of their nose would still come out at the back of the throat and then leading from there the wind passes across the top of the throat where the nasal passage meets it, and down to the bottom where it meets the trachea (making it so throat and wind pipe 'intersect'). When a dolphin swallows food it still has to pass that food over the top of the flap (technical term) which seals off the top of the trachea. This should mean that if the dolphin swallows it could still end up getting food down if it managed to "snort" at the same time?

[Svartalf]

Yes, but you wouldn't need to if you had a hole on top of your head

How do I know that wouldn't get clogged too?

[Animavore]

Ok. I just Googled Can dolphins choke?

[rachelbean]

All I know for certain is that the lungs and esophagus are not connected at all which is why they can't choke on their food the way we do. They could still get their blowhole blocked for other reasons, but they usually clear them with a forceful blow that is many times more powerful than our sneezes.

[Animavore]

All I know for certain is that the lungs and esophagus are not connected at all which is why they can't choke on their food the way we do. They could still get their blowhole blocked for other reasons, but they usually clear them with a forceful blow that is many times more powerful than our sneezes.

But how can that be without a total redesign of their tract?

[JacksSmirkingRevenge]

[mistermack]

It's us humans who have the unusual setup.

Chimpanzees can't choke on their food either. If a chimpanzee goes unconscious, there's no need to put it in the recovery position, or clear the airway. We humans evolved a descended larynx, very different to other apes, when we started speaking.

I believe that our larynx starts out higher, and gradually descends, either in the late stages of pregnancy, or in the first few months after birth.

I used to know the details, but it's fuzzy now.

[rachelbean]

All I know for certain is that the lungs and esophagus are not connected at all which is why they can't choke on their food the way we do. They could still get their blowhole blocked for other reasons, but they usually clear them with a forceful blow that is many times more powerful than our sneezes.

But how can that be without a total redesign of their tract?

I don't understand the logic. They didn't evolve from humans. We share common ancestors and they are mammals, that doesn't mean they evolved the same in all ways or didn't continue to change/develop after the split from those commonalities

[Animavore]

All I know for certain is that the lungs and esophagus are not connected at all which is why they can't choke on their food the way we do. They could still get their blowhole blocked for other reasons, but they usually clear them with a forceful blow that is many times more powerful than our sneezes.

But how can that be without a total redesign of their tract?

I don't understand the logic. They didn't evolve from humans. We share common ancestors and they are mammals, that doesn't mean they evolved the same in all ways or didn't continue to change/develop after the split from those commonalities

Even reptiles share commonalties in our nasal structures. This is how old they are. Except in reptiles they don't have a cleft palate, which in mammals closed over time separating the mouth from the nose (reptiles can stick their tongue out their nose).

[Mysturji]

Over millions of years, the mammalian line that eventually evolved into cetaceans gradually adapted to their environment.
Part of this adaptation was that the orifice they breathe through moved to the top of their heads - away from the orifice they eat with.
In most land-dwelling mammals (and some water-dwelling ones) those two orifices (orifii? ) converge partway down due to a lack of space in the neck.
Cetaceans no longer have that problem.

[mistermack]

All of the following is speculation on my part.

Land animals find it convenient to be able to breathe through the nose AND the mouth because :
1. It's good to be able to filter out dust, when breathing normally, but when running etc, to be able to open up the mouth, and gulp in more air.
2. Land animals often need to humidify the air, to keep the lungs healthy, and to re-claim moisture, as in camels, when breathing out, so they need a bigger surface area, in the nasal passages.
3. The nature of a nose that effectively filters the air means that it can clog, so you need to be able to breathe through the mouth.
4. Many land animals use their sense of smell to find food and avoid predators, so a nose that filters air is important for that.

Cetaceans have to be able to take huge deep breaths very fast, so their noses are wide open, and are never going to clog.
They are always breathing very humid air, which has very little dust, and they don't need to conserve water. And the sense of smell isn't too important under water. So they can have big open nostrils, with as little restriction as an open mouth.

[Brian Peacock]

I was thinking about how they make and use sound to understand the environment. We all know the theory - they make a sound and interpret the reflections allowing them not only to perceive the position of the objects around around them, but also to get some information about their density and structure. Dolphins live in the open ocean, silted rivers and river basins, they have to get about at night, deal with colossal ocean storms, and find food wherever they are and whatever the conditions. Sound travels more quickly in water than in air but its carrying power is proportional to its frequency and its amplitude. Low frequency sounds carry further but because of their wavelength are less accurate than higher frequency sounds. And the aquatic environment isn't quiet, so the toothed whales have a lot of information to juggle with and process and map into whatever their conception of the environment is. Pretty cool.

This was in the news a couple of weeks ago....

Dolphins 'call each other by name'

Scientists have found further evidence that dolphins call each other by "name".

Research has revealed that the marine mammals use a unique whistle to identify each other.

A team from the University of St Andrews in Scotland found that when the animals hear their own call played back to them, they respond.

The study is published in the Proceedings of the National Academy of Sciences.

Dr Vincent Janik, from the university's Sea Mammal Research Unit, said: "(Dolphins) live in this three-dimensional environment, offshore without any kind of landmarks and they need to stay together as a group.

"These animals live in an environment where they need a very efficient system to stay in touch."

Signature whistles

It had been-long suspected that dolphins use distinctive whistles in much the same way that humans use names.

Previous research found that these calls were used frequently, and dolphins in the same groups were able to learn and copy the unusual sounds.

But this is the first time that the animals response to being addressed by their "name" has been studied.

To investigate, researchers recorded a group of wild bottlenose dolphins, capturing each animal's signature sound.

They then played these calls back using underwater speakers.

"We played signature whistles of animals in the group, we also played other whistles in their repertoire and then signature whistles of different populations - animals they had never seen in their lives," explained Dr Janik.

The researchers found that individuals only responded to their own calls, by sounding their whistle back.

The team believes the dolphins are acting like humans: when they hear their name, they answer.

Dr Janik said this skill probably came about to help the animals to stick together in a group in their vast underwater habitat.

He said: "Most of the time they can't see each other, they can't use smell underwater, which is a very important sense in mammals for recognition, and they also don't tend to hang out in one spot, so they don't have nests or burrows that they return to."

The researchers believe this is the first time this has been seen in an animal, although other studies have suggested some species of parrot may use sounds to label others in their group.

Dr Janik said that understanding how this skill evolved in parallel in very different groups of animals could tell us more about how communication developed in humans.

video: http://www.bbc.co.uk/news/science-environment-23410137

[Sean Hayden]

Wow, that's really cool.

[mistermack]

It would be interesting to compare the breathing arrangements of sea lions, seals and dolphins, to see if there is a sort of natural progression of reducing the mouth-breathing ability across the range.
It's a shame that there isn't an animal that is making the transition, from giving birth on land, to in water.
Maybe a fossil might turn up, but I imagine it would be a quick transition in evolutionary terms, so the chances of fossils turning up would be slim.