Questions related to mammals.

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Body part in motion after decapitation?

I'm sure following video is totally different than of other mammal after their body parts decapitated. In this video apparently, the snake is cut into three pieces. But when we look closer to the ...
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1answer
92 views

What species of fox is this?

I found this picture of a fox in a news article about arctic foxes in Sweden (source), but I'm not sure whether it is actually an arctic fox. On the one hand, it has white fur, which is the correct ...
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1answer
91 views

Can kit foxes and red foxes produce offspring?

Can a kit fox (Vulpes macrotis) and a red fox (Vulpes vulpes) together produce offspring? Would such a hybrid be fertile?
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1answer
69 views

Identification of a small mammal

Could someone help with identification of this small mammal? Is it a possum? A dormouse? It was photographed in Sukhumi botanical garden, in Abkhazia (west of Georgia, on the shores of the black ...
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2answers
478 views

Why haven't land animals evolved beyond urination?

It occurred to me (while urinating) that this would seem to be selected against because water is a scarce resource. Why are we constantly losing water we don't need to through urination? What is ...
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0answers
45 views

Why is a wound much more painful when damp?

Why is a wound much more painful when damp? This is a very strange phenomenon. For example: I have a little wound, not painful at all. But, when it is just damp, it is much painful.
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Pineal gland of a Chimpanzee

I have found it rather hard to find a single photo of a Chimpanzee's Pineal Gland in cyberspace. I would like in particular to view the pineal gland of Chimpanzee that deceased of old age just to see ...
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23 views

Are there biological safeguards to compensate for male primate infertility?

I'm trying to understand human sexual selection, and the following question has been on my mind for some time. I don't know the exact terminology to do a quality scholarly search on the subject. Are ...
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0answers
20 views

Omnivore vs Carnivore territory size

Edit: Large carnivores require lots of territory. What about bears? They're omnivores. How much does that count? Is there anywhere I could find weight/territory ratios for mammals, depending on diet? ...
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1answer
49 views

What are these curious cetaceans?

At the beginning of the superb documentary film “Un jardin d’Eden sous les mers” (“A garden of Eden under the seas”) [1], we see a group of curious cetaceans. At about 1 min. What are these ...
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42 views

Why were dinosaur skeletons so light compared to mammal skeletons?

I was watching a presentation by Dr. Jessica Theodor [1] who discusses (at 38:10), among other things, the skeletal structure of dinosaurs vs. mammals. "Dinosaurs have way lighter skeletons, which ...
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1answer
36 views

Why can one swim longer underwater by blowing out air?

I am a human. I take a deep breath. I swim underwater... After some time, I need to blow out some air. I blow out some air... By doing so, I can swim underwater longer. Blowing out some air gives me ...
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2answers
5k views

Are there any non-mammalian species known that lactate?

Are there any non-mammalian animals that produce milk to feed their young, or are mammals the only milk-producing animals?
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1answer
2k views

Evolutionarily, why do male rats and horses lack nipples?

Developmentally male rats don't have nipples because (reddit) Testosterone release in the fetal male rat happens before the stage of mammogenesis where the teat is formed whereas other species ...
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0answers
27 views

How is the brain kickstarted during development [closed]

The brain is a complicated beast, that operates (generally) by electrical activity. During development, all cells originate from the a single "cell": the zygote. At some point during development, the ...
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0answers
19 views

Is it possible for two creature in the same order and have odd haploid chromosome species to reproduce

Take the degu and the rat for example. The degu has 29 chromosome pairs Rats have 21 chromosome pairs. They are only share the same order ( Rodentia ) Would it be possible for them to reproduce? ( ...
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0answers
49 views

How did dolpins acquire the dorsal fin?

I had been thinking bout atavism when I saw a picture of a dolphin. I had seen it before, but suddenly the dorsal fin startled me. How did this dorsal fin evolve, especially, is it some atavism from ...
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0answers
50 views

What is the reason for fear induced defecation?

I started to handle mice for my job and noticed that they tend to defecate and/or urinate when they are scared. The fear is induced by me, because I need a long time (due to inexperience) to grab the ...
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26 views

Do elephants get thorns out of each other's skin?

I have watched Wild Kratts Elephant in the Room several times where a baby elephant named Thornsley has a big thorn in his foot and is nowhere near his mom. This along with herd members helping each ...
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1answer
143 views

Why does snow not stick to the fur of wolves and some breeds of dogs?

This question made me wonder, why for example wolves don't suffer from these "paw snowballs"? (...) but after a few miles on the trails in soft snow, he often develops snowballs between his paw ...
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1answer
43 views

Whales and cancer [duplicate]

Do whales get less cancer than they should considering they have a lot more cells and tissue? If a lot of cancer formation is random because of mutations then shouldn't whales receive a lot of ...
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0answers
92 views

Why do mammals produce more carbon dioxide than insects?

I understand that mammals produce more carbon dioxide than insects on a gram per gram basis, but why is that? I'm thinking it might be because mammals are warm-blooded, which require more energy ...
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1answer
173 views

Is it theoretically possible to restore the Tiger population to 100,000?

The current global Tiger population is roughly 5100 according to Wikipedia. With habitat destruction and poaching continuing and no effective improvement in conservation, most likely the Tiger ...
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2answers
2k views

Why do rabbits often have white hindquarters?

There are several species of herbivores that have a very visible white hindquarters: several kinds of deer, rabbits, antelopes, etc. Does the white fur serve a functional purpose, or is it purely ...
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1answer
96 views

Do camels pose an environmental threat to kangaroos?

Camels, once used for transport across the Australian outback, were set free, and are reproducing at an uncontrolled rate in the empty interior of Australia. Do the ecosystems of camels and ...
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1answer
202 views

Why does the kidney of a cow have lobules, why the kidney of a human hasn't any?

The kidney of a cow has lobules, while the kidney of a human hasn't any. I can't think of any reason why it would be good for a kidney to have lobules. It would be good if the kidney needed to have a ...
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1answer
162 views

What effect does a bat's echolocation have on other bats?

Bat echolocation is a perceptual system where ultrasonic sounds are emitted specifically to produce echoes. By comparing the outgoing pulse with the returning echoes, the brain and auditory nervous ...
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1answer
238 views

Are the byproducts of mammalian digestion simply depleted versions of the food or liquid consumed?

When mammals consume food and digest it or drink fluids that are then filtered by their kidneys, are the waste products generated simply depleted versions of what they consumed? Are there other ...
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1answer
69 views

Red fox with blue legs

On the Wikipedia I found this photo of a red fox, labeled as being taken at Quesnel Lake, British Columbia: Why would the fox have blue legs? Is that normal for a Red Fox?
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1answer
7k 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
62 views

How does the Platypus grow before it eats?

From this fascinating documentary on monotremes it is mentioned that the Platypus is born less than 1 cm in length, but has doubled its size by day three when it begins to nurse. How does the animal ...
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1answer
171 views

Do mammals and birds have a common warm-blooded ancestor?

Is it homogeneous or did they converge? Did we both evolve from warm-blooded reptiles that are extinct maybe?
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1answer
356 views

Mammal body density

Human body density is approximately 1 kg/l (same as fresh water) - which is not surprising (at first) given that we are 70% water, and is surprising (on a second thought), given that the other 30% can ...
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5answers
10k views

Why don't mammals have more than 4 limbs?

Arthropods have 6 or more limbs and arthropods with 6 limbs appear to move faster than arthropods with 8 limbs so I wonder whether this might have something to do with fast and efficient locomotion. ...
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52 views

What is a common body composition in mammals?

The Physiology Of The Racing Greyhound states that most species have about a 40% muscle mass to body mass ratio. Understanding Body Composition puts "optimal fitness" in humans at 16-25% body fat for ...
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1answer
802 views

Why have whales and dolphins not evolved to have gills?

It seems at first glance that it would be an evolutionary disadvantage for a sea creature to have to come up to the surface on a regular basis in order to breathe, so why are there animals (e.g. ...
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2answers
289 views

Why do squirrels have twitchy bushy tails?

Whenever I see a squirrel in the woods, it is always the big bushy tail flipping around that gets my attention first. A pray animal with a big bushy flag calling attention to it's self seems to be ...
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1answer
41 views

Heteromaternal Superfecundation - Any known cases?

Superfecundation in mammals (fertilization of two or more ova from the same cycle by sperm from separate acts of sexual intercourse) -- Is possible in nature from different fathers (Heteropaternal) as ...
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1answer
35k views

Can a person really die quickly from biting their tongue?

A common trope in certain circles (like Eastern martial fiction), is someone committing quick suicide by biting his or her tongue. But is this really possible? The internet turns up millions of ...
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1answer
5k views

Why can't humans drink sea water?

Why can't humans drink sea water? It would seem to be a huge evolutionary advantage for an animal to be able to drink sea water rather than have to rely on fresh water, and it's provably not ...
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0answers
12 views

Does level of bats activity differs from day to day?

Say we measure bats activity as number of passes through given area. Can it differ significantly depending from day to day or it stays on average roughly the same? I am wondering whether the following ...
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1answer
83 views

Can dolphins actually communicate linguistically?

Humans use "language." By language, I mean the thing I am using right now to talk to you. I know dolphins and orcas have very complex communication systems and also seem to process linguistic and ...
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0answers
58 views

Is there a comprehensive model of human attraction and sexuality? [closed]

I'm interested if modern (2015) biology has a comprehensive model of how human sexuality works. From my research, it appears that the drive for mating is primarily mediated by ...
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1answer
67 views

The ermine's colour and geographical range

Ermines turn white during the winter, with only the tip of the tail remaining black. However, in the southern regions of the ermine's range it clearly doesn't get so white. Encyclopedia of Life says ...
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1answer
89 views

Why do surface mole tunnels follow directly below the electric fenceline

I have electric fencing enclosing five acres, and moles always seem to tunnel in a straight line just under the electric fence - are they following a force field? Can that be?
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2answers
65 views

How can bats achieve good resolution with wide beams?

I have been reading about the echolocation system in bats. papers state that bats tend to produce a sonar beam that has a beam angle (-3db) of about 30-40 degrees. This would be considered a wide beam ...
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1answer
48 views

Why do teeth decay of sugar?

Sugars is a common component in diet of mammals. Why then their teeth did not develop resistence to sugar decay?
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1answer
71 views

Mammal vs Placental Mammal

So for Google Earth Day's quiz I ended up being a "Pangolin." Turns out I had no idea what it was so I looked into it and honestly it reminded me a lot of an Armadillo. So I decided to find out the ...
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2answers
6k views

How and why did mammals go back to the oceans?

If I understand evolutionary biology correctly, mammals first evolved on land as small, rodent-like creatures, in a time when reptiles were dominant on land. Eventually, they diversified into the ...
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Why there are two rounds of cytosine de-methylation in mammalian development?

I assume that the key biological meaning of cytosine de-methylation during germline development in germline progenitor cells is to reset imprinted genes and then set methylation pattern on these genes ...