The biological study of animals.

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How is the blood volume of a living organism measured without killing it?

How is the blood-volume of an organism measured without killing it? NOTE: The blood-volume of an organism is defined as the total volume of blood present inside that organism.
5
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1answer
166 views

What evolutionary mechanism caused felines to develop purring?

And why can some felines roar while others meow?
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1answer
3k views

Fish “coming back to life” after being frozen

I've encountered a clip on Youtube showing a goldfish thrown in liquid nitrogen and immediately after to normal water and swimming normally. In the explanation to the clip it says: For everyone ...
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1answer
1k views

Will the “frog in boiling water not jumping out” work on warm blooded animals

There is the famous saying about a frog that is put in water that are slowly boiling will not jump out until it's too late. I realize it happens because of the frog's cold blood that adjusts to the ...
6
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1answer
195 views

Effect of spaying on the female cat organism and health

Veterinarians often recommend spaying a female cat if the owner does not want her to have kittens. What does biology know about the effect of spaying on female cats' organism and health (apart from ...
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3answers
1k views

Species with reproduction barriers that can both reproduce with a third species

To start with, I do not have a sound knowledge in biology or any formal education in the area. I was told that one of the definition of a species is a reproductive barrier, which means that if two ...
12
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3answers
456 views

Why is there a difference in the rotation of the tail fin in fish compared to marine mammals?

I've been thinking about this one, but I can't seem to find what causes this difference. All fishes that I've seen have their tail fin positioned vertical: But all the marine mammals I know have ...
11
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3answers
649 views

Is the appendix a vestigial structure in all vertebrates?

In humans the Appendix is a vestigial organ. Does it serve no apparent purpose in all the vertebrates that have one?
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1answer
175 views

Are there any other animals that become attached to a non-living object?

Do any animals become psychologically attached to any non-living object that is not useful to the animal for any of its physical needs, like some children do to stuffed animals? Some children are so ...
7
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1answer
218 views

Could an animal with an open circulatory system survive in a near-zero gravity environment?

An animal such as a crayfish relies on gravity to keep its circulatory system running. If it is turned upside down, the gravity works against the system, suffocating the animal. Now if, instead of ...
8
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2answers
255 views

What's the name of this bird?

This morning I saw a bird that I have never seen before. Since it was quite big, I'm very interested in knowing its name. The bird was quite big, at least 2-3 times of a common blackbird. The wings ...
8
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2answers
389 views

Why is blood pressure higher the more distal an artery is?

Why is blood pressure generally higher in more distal arteries?
11
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2answers
332 views

Why do pandas have a high probability of giving birth to twins?

According to the BBC documentary "Wild About Pandas", about half of panda birth result in twins. Why do they have such a high probability compared to other mammals? What factor(s) control that ...
8
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2answers
202 views

Why do animal teeth get darker if exposed?

I was wondering why the teeth of cats (And dogs, as far as I know, plus possibly some other animals or even humans) get darker if they are exposed to air / light? Example: (See the lower end of ...
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2answers
2k views

How do insects breathe?

Do ants even breathe? If they don't, how do they stay alive? On what resources do they depend upon to stay alive? How are they different form mammals?
8
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1answer
754 views

How strong is spider silk?

Spider silk is pretty darn strong and all sorts of comparisons are made to steel. I'm more curious about the various moduli of spider silk and how it compares to other materials. What is the Young's ...
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3answers
1k views

Fetal development, gastrulation and embryonic disc

I am completely confused by the images circulating on the internet of human gastrulation. First, lets see how it happens in deuterostomes. This image depicts the process: (image is from Wikipedia) ...
4
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1answer
256 views

What did pangolin scales evolve from?

Were they developed anew or a heritage from fish?
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2answers
102 views

Is there a term for tool use in animals?

Is there a technical/scientific term that scientists use to refer to tool making abilities found in certain types of animals? Reference ...
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2answers
4k views

Why is it that cats can jump so high for their size, compared with humans?

My cat is about 1' high at the shoulder, and I am a little over 6', but my cat can easily jump onto something as high as I am. That is 6x it's height. If a cat can do this, then Why can't I jump up ...
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4answers
5k views

Do cows produce milk excessively?

Do cows produce more milk than it is required for their calves? It seems like cows are able to provide milk all the time (all year around). Is it so? Or do they, like other mammals, produce milk only ...
13
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1answer
471 views

How do porcupines keep from pricking each other while mating?

How do porcupines keep from pricking each other while mating? It seems like they would constantly be scratching each other.
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1answer
2k views

How many mice are on the Earth?

We are 7 billion human beings on the Earth. But how many mice are there? How would you estimate such a number?
7
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1answer
434 views

When do most mammals mate?

Is one part of the day more prevalent then other when it comes to mammal animals mating? Is there an aggregating study that has been done to see if these living beings in nature mate mostly during day ...
8
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1answer
200 views

Which organism has the sharpest vision?

Which organism has the sharpest vision in terms of distance and spectrum. Please propose any other useful measure.
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3answers
3k views

If I put a cup over a spider, and leave it there for a day, will the spider survive?

Will it travel more slowly since it hasn't had food for a day? What if I left the cup there for longer?
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2answers
571 views

What are the trajectories of flying insects?

Many flying insects tend to have very jagged trajectories. For moves of a fruit fly looks like a random walk. Is there any research on the properties of trajectories (e.g. their fractal dimension or ...
11
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1answer
297 views

How do members of cryptic species know who to mate with?

According to Wikipedia: In biology, a cryptic species complex is a group of species which satisfy the biological definition of species—that is, they are reproductively isolated from each ...
8
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1answer
199 views

Is the squid giant axon the fastest conducting unmyelinated axon known?

The conduction velocity of the squid giant axon can reach 30 m/s. Is there any known example of an even faster conducting unmyelinated axons?
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3answers
273 views

Where can I find the common names for the zoology taxonomy?

Forgive me if my question does not belong here or if I'm using incorrect terms, but I'm not educated in biology at all. I'm investigating the workings of the biological classification system. I was ...
11
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1answer
193 views

Are there any pre-Holocene venomous animals?

The novel (and subsequently movie) Jurassic Park featured a dinosaur called Dilophosaurus, that was purported to be venomous and had an ability similar to that of the extant spitting cobra. ...
17
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1answer
202 views

Are there dextral/sinistral higher animals?

For example, almost every dog I've met in my life (more than 20 subjects) uses their right paw touching one while asking for attention. Can it be used as a criterion for calling them dextral? If not, ...
14
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1answer
570 views

Do large animals often evolve into smaller animals?

There are several examples where the largest animals were killed off preferentially due to a major ecological shift: The KT extinction event The Holocene extinction, as well as the major megafauna ...
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2answers
1k views

How do cockroaches resist the effects of ionizing radiation?

Cockroaches are very hardy insects. It is known that, among other things, they are able to withstand bursts of ionizing radiation that would kill a human being. The explanations of this observed ...
10
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1answer
299 views

Examples of animals that co-opt toxins?

It is known that there are animals that acquire toxins through their diet or through their surroundings. The examples I know of include butterflies stocking up on alkaloids/glycosides while in the ...