The biological study of animals.

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Transitivity of Species Definitions

There are many definitions of "species" which usually take the form Two individuals are of the same species if ... An implied (rarely made explicit) property of any sensible species definition ...
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69 views

Identifying internal structure of dissected prawn

Note: Some of the images might be disturbing. I have dissected prawn for the first time. Would like your help in identifying some structures . This is the dissection of the posterior part of the ...
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Does artificial high intensity light damage permanently dark ecosystems?

Popular science features on wildlife typically capture camera images using natural light, or high-speed exposures. This is not possible where the ambient light is extremely poor. E.g. Caves, Undersea ...
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80 views

In an open circulatory system, how is blood moved?

In the mollusks section, the powerpoint mentioned that gastropods and bivalves have an open circulatory system. According to the note, this means that the blood does not travel in vessels. How, then, ...
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68 views

Can I force evolution in a group of cells by removing all the smaller cells?

I actually have algae growing in water in a container. I was thinking if it was possible to filter the water so that all the small cells will be filtered out and only the bigger ones will remain to ...
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223 views

How do we know that dinosaurs were related to lizards and/or birds?

Do we clearly know what the living closest relative of the dinosaurs are? And connected to the first question, in scientific manner how do we know these relationship between extinct species and living ...
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Why are there no wheeled animals?

In physics, "almost everything is already discovered, and all that remains is to fill a few unimportant holes." (See Jolly.) Therefore, on Physics SE, people are veering off into different directions: ...
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339 views

Why are there ecosystems?

Why would things self-organize in such a manner? I'm a mathematician and I have no baggage in ecology or biology. If the question is too broad maybe someone can point me to formal sources where this ...
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42 views

Book recommendation on selective breeding?

I am looking for a good book that gives a nice overview of the science and technics of selective breeding. I am particularly interested in the use of population genetics to support decision in this ...
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34 views

List of the biggest companies that work in selective breeding

Looking at this question, I've been wondering, What are the biggest private companies which work in both animal and non-animal selective breeding? Let me know if Biology.SE is not appropriate for ...
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33 views

Burns' “To a mouse” - what species of mouse?

What's the most likely mouse species Robert Burns is referring to in his poem "To a Mouse, on Turning Her Up in Her Nest with the Plough". Burns farmed near Ayr, which is on the Firth of Clyde in ...
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1answer
196 views

How do pet gecko lizards pose a health risk?

Does having gecko lizards living in your house pose any health risk?
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1answer
60 views

Do chicks in eggs excrete?

I want to know if, as a baby chick grows inside the egg, does it excrete waste? If it does excrete waste, does the waste just sit inside the egg with the chick, until the chick cracks open the egg ...
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Are there specific features of birds that cats/small predators are attracted to?

I've recently heard a podcast, in which a professor describes one of the theories as to why we like abstract art. In his talk, he mentions an experiment with seagull chicks, in which the seagull ...
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33 views

How did the roar evolve from snort?

When Lions roar, or Dogs show aggression, they do that snort-roar thing. They're producing sound while inhaling. How did that come to be when all (?) other forms of sound involve exhaling? Humans do ...
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39 views

Visualisation of phylogeography

I am working on phylogeography on one model species and I am a beginner. You can imagine one species that came on locality more than 5 mya (million years ago). It was a good environment, so the ...
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1answer
2k views

Why do we grow so much hair on our heads compared to our bodies?

I've been wondering about head hair, facial hair in particular. Human males can grow very extensive beards should they choose to not shave - however you do not really see this in our chimpanzee ...
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137 views

Why is Portuguese man o' war considered a colony?

The wikipedia entry on the Portuguese man o' war says: ... the Portuguese man o' war is ... not actually a single multicellular organism but a colonial organism made up of many highly specialized ...
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87 views

Why can we breathe only oxygen?

Plants has the capacity to take in both CO2 and oxygen, that's during day CO2 and at night oxygen. Why don't humans have such a capability?
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3k views

What's the difference between a plant and an animal?

Are there some living things where the distinction between plant and animal is blurry or unclear? I wouldn't know where to put something like yeast. I also thought of photosynthesis, but then I ...
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Can all mammals swim?

When I checked it seemed trivial to answer: yes, all mammals can swim. But research on the internet provided different information. I found: people and primates cannot swim, but can be taught how to ...
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4answers
1k views

Why we have no enzyme to digest cellulose?

As we know, cellulose is the most abundant polysaccharide in nature. Why don't we have any enzyme to digest cellulose?
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166 views

Sexual selection in cats or other animals

I was wondering if you could answer some of my questions regarding sexual selection in cats (or any other animals). I would like to apologize beforehand for my incorrect term use. When it comes to ...
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1answer
65 views

Are these bat social calls?

I'm currently researching bat social calls (not echolocation calls) and have been given a series of samples (in .wav format) and wanted to know, if what I can hear is actually the social calls. Below ...
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1answer
212 views

Why apes started to contemplate and become altruistic? [closed]

I was asking this first on philosophy forums, but it is suggested, that answer could be found from evolutionary view of point, so here we go: Again my question raised when thinking of myths, their ...
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The least complex animals with ability to dream

People can dream, dogs can dream, cats probably too when they are sleeping. What about other creatures? Can a bird dream? Do rats have dreams? Are there any studies about that kind of thing? What ...
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1answer
43 views

Clownfishes and Sea anemones

Relation between clownfishes and sea anemones is a classic example of mutualism. I wanted to list the species of sea anemones that are involved in this mutualism but I got lost.. Could you help me ...
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56 views

Dogs bark at familiar person in Santa costume. Why? Don't dogs trust smell over vision?

Last night 10 humans and 2 dogs spent Christmas together. At some point, one human dissappears for a few minutes and comes back wearing a full Santa outfit. Upon respawning, the dogs start barking ...
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What is the life span of southern versus northern animals?

How long do wild animals of the northern hemisphere live compared to those of the southern hemisphere and based on their growth span. Particularly large mammals and particularly animals of similar ...
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54 views

Can pets catch the cold?

Last night I was drying my cat with a towel after shenanigans in the rain and she sneezed! Questions Can cats/dogs/hamsters or other pets catch the cold? How quickly do they recover?
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Temporal effects on pathways?

I was wondering whether or not there exist certain pathways that are triggered by a temporal signal. We're almost at the winter solstice now. Does animal or plant function involve signals that are ...
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2answers
241 views

How to know if a woman is fertile without actually making her pregnant?

How to know if a human female is fertile (can give birth to child in future) without making her pregnant? Any signs, tests?
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1answer
63 views

Niche overlap Index

I wanted to use the compana() function from the adehabitat package. I don't really understand the meaning of the data in the ...
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1answer
92 views

What are the visual, behavioral similarities and differences between Yellow Fever Mosquito (Aedes aegypti) and the Tiger Mosquito (Aedes albopictus)?

The Tiger and Yellow Fever Mosquito visually look very similar. Recognizing the difference is important for tracking and controlling the spread of Yellow Fever, Dengue fever and other diseases. ...
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2answers
377 views

The number of nipples (breasts) a species has?

Only mammals have mammaries and mammary glands. What evolutionary factors determines the number of mammaries (nipples/teats/breasts) a species has? Is it always an even number?
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169 views

Excretion of various wastes and water requirement

A common fact is that Ammonia, Urea and Uric acid are the most common excreted metabolites and their removal needs varying amount of water, highest for ammonia (hence suited only for aquatic animals) ...
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62 views

Organisms with the most extreme sensory capabilities? (sight, smell, sound) [closed]

Background It is quite mind boggling to imagine what it would be like to be missing sight, sound, touch, smell, taste etc. Question Which organism holds the record for most extreme sensory ...
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1answer
110 views

Cats, Dogs and Bears - how are they related?

What is the ancestral relationship between cats, dogs and bears? I presume they are more closely related to one another than other paraphyletic clades of mammal. Which came first? What did their ...
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1answer
101 views

Are these cats calico?

Calico cats are cats that have 3 fur colors and are always female or males two X chromosomes. I've seen many cats that will have 2 fur colors (one of them is usually white) and another, third, color ...
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139 views

Do animals suffer from “Human” mental disorders?

It is tragic, but apparently Killer whales and Dolphins can commit suicide too (e.g. here)... This suggests they can become depressed. I wondered whether they were "clinically" depressed like many ...
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1answer
84 views

Can anyone identify this caterpillar / cocoon?

This insect is about 0.5 mm in length, so it is very small. It doesn't have legs I don't believe, I am not too good at this but I don't know if it's a worm or more like a cocoon for something. I do ...
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86 views

Body size, what are the evolutionary trade-offs?

Background Considering just the "Kingdom Animalia" branch of organisms. It is clear that bigger does not necessarily mean better - there is large variation in body size... From the 94 µm long ...
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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 ...
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1answer
106 views

What are the universal laws of Nature concerning animals' behaviour? [closed]

I'm looking for very old (centuries) treaty or recent (20 & 21th century) research that state what some of the laws of Nature are, particularly concerning wild animals' behaviour. Such as; every ...
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1k 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?
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1answer
147 views

Is there a difference between pig and cow anatomy that makes religious slaughter of the latter less painful?

This question is not for the squeamish. I was told that non-Kosher animals like pigs have a different anatomy in their neck compared to kosher animals like cows such that the Shechita method of ...
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70 views

Praying Mantis (female) put sticky white stuff on wall of aquarium

Anybody know what this sticky white stuff is? She had a foot stuck in it; I had to help her get it loose. Was she purposely gluing herself there (perhaps in preparation for molting), or is she sick? ...
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3answers
11k views

Small worm living in some kind of cocoon, what are these animals?

I am curious what animal is this. It is/lives inside some kind of cocoon, about 1 cm in length. They are attached to walls and to the ceiling, but sometimes they fall off. Inside the structure there ...
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1answer
337 views

Do bigger animals have more testosterone?

I was wondering the other day outside, thinking about varieties of species and their aggression levels, etc. I had a theory that since these highly aggressive, powerful, and viciously advantageous ...
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1answer
157 views

Why does the gender of the parent species determines the species of a hybrid offspring

I've read a little about hybrid animals, and have been amazed by the fact that the gender of the parent species determine the species of the offspring, in some hybrids. A male horse and a female ...