Questions related to mammals.

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3
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1answer
138 views

How do Kangaroo mothers deliver the correct kind of milk to the correct joey?

Mother kangaroos are able to rear multiple joeys (young kangaroos) at different stages of development at the same time. According to Wikipedia, "the mother is able to produce two different kinds of ...
3
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2answers
585 views

What is the fastest marine mammal?

When I did a research, most of the sources say that orca is one of the fastest. But I could not find a source that says it is actually the fastest. Some sources say that Dall's porpoises rival orcas ...
2
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1answer
77 views

GULO only for mammals?

I am not a biology student, but just want to know if GULO gene are present only in mammals or all species possess it ? And is GULO gene active in human fetus?
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1answer
91 views

Why do mammals in the wild retain the “trait” of menstruating with blood?

This question intrigued me a lot since if animals in the wild did have menstruation with blood flow, wouldn't all that blood be attracting every other predator in the vicinity?
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2answers
2k 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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1answer
5k 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 ...
7
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5answers
3k views

Why do most mammals have long snouts?

It seems like most mammals, e.g. dogs, have long snouts. My pet dog's snout would seem to me like an evolutionary disadvantage, since her canine teeth are way out at the end of her jaw, which acts as ...
5
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1answer
67 views

How do rodenticides with delayed effect work?

Most modern rodenticides are claimed to cause death no earlier than several days after ingestion. That's quite strange - once a chemical was ingested it will be absorbed in the digestive system and ...
3
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1answer
237 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 ...
10
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3answers
912 views

Why is mammal coloration so dull?

I have seen species of birds, insects and fishes with splendid colours. But when it comes to mammals (including us humans), they almost always appear in shades of brown, grey, orange, or in black and ...
6
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2answers
573 views

Goats are so fearless but sheep are not. Is there any genetic difference responsible?

As you see in the picture goats (not only wild goats) are so fearless, but I never saw any sheep do this. What is the source of this difference in behavior?
3
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1answer
513 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 ...
4
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1answer
228 views

How are blood vessels affected by UV and infrared radiation?

The lining of the blood vessel as an interface and boundary layer is of existential necessity to the life-support of mammals. My question is: How are major blood vessels and the blood vessel lining ...
2
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0answers
379 views

Can Squirrels Eat Every Mushroom? [closed]

Squirrels have the ability to eat toxic mushrooms as described below. Are there any mushrooms that they can't eat without dying? According to Dr. John Rippon, an IMA member and world expert on ...
6
votes
1answer
81 views

How compatible are mammal wombs?

I had read about science working towards the creation of artificial wombs however I wonder how compatible are mammal wombs and connected systems to develop fetuses. What species are so compatible that ...
4
votes
1answer
676 views

Why do sloths come down from the trees to defecate?

I'm under the impression that most sloths exhibit this behavior, but why? They are slow moving and so have no way of escaping from predators when on the ground. Not to mention the energy they expire ...
3
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2answers
113 views

Do dolphins really sleep?

I have always wondered, if dolphins sleep with one eye opened, do they really sleep at all? According to this article dolphins indeed shut down their brains. I already googled it. No help from ...
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1answer
194 views

Are ape communities more “anarchist” or “communist” in structure?

I am using these terms because we can imagine them quite good, I guess ;) By "anarchist" I mean that the ape wants to live without the rule of others apes(same biological race or other) and he pursue ...
3
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1answer
104 views

How compatible are mammalian digestive systems?

I'm interested in what kinds of nutrients mammals extract from food and would like to know how similar are the outputs of these systems. For example, if it is possible to successfully replace one ...
15
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1answer
31k 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 ...
3
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2answers
541 views

How do bats distinguish between day and night?

How do bats distinguish between day and night? Do they hunt at night - if yes, how they know that? Are they afraid of sunlight?
2
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0answers
114 views

Are there any mammals in which polyspermy produces viable zygotes?

Are there any mammals in which polyspermy produces viable zygotes? In the wikipedia page it is mentioned that there is a delicate equilibrium between female defenses against many sperms, which ...
2
votes
2answers
508 views

Do any cells change in size or mass as mammals grow?

That is to say, are there cells that, between infancy and adulthood, get larger? Or is all growth done entirely via cell division? I'm wondering if it is safe to assume that the approximate number ...
10
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1answer
1k views

Could a fetus properly develop in micro/zero-gravity?

I suppose another way of looking at the question is: how important is gravity for the development of mammal fetuses? And if things would go wrong, what sort of things would they be, and what would be ...
5
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1answer
364 views

Do any birds beside the family Columbidae (or any reptile or mammal) feed their young “Crop Milk”

Birds from the family Columbidae (e.g., doves and pigeons) produce a fatty, milk-like substance in their crop. The secretion is often referred to as "crop milk." They feed crop milk to their young ...
8
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1answer
713 views

What hair do aquatic mammals have?

I'm reading an essay on the creating of the Mammalia zoological classification (Londa Schiebinger, The American Historical Review, Vol. 98, No. 2 (Apr., 1993), pp. 382-411). It contains the statement ...
5
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1answer
181 views

What selective factors drove the evolution of lactose in lactation?

As far as I can determine, lactose, and the monosaccharide galactose have few biological uses outside of mammalian lactation. It not only required enzymes for its production, but enzymes in offspring ...
6
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2answers
186 views

Do omnivore mammals vary food preferences based on dietary needs?

I'm wandering if mammals that can eat many different kinds of food (omnivores) vary their preference for food not only based on the availability, but also based on dietary needs? I'm looking at this ...
16
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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 ...
6
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2answers
12k views

Do other male mammals except for humans have nipples?

When I grew rabbits, I had a pair, one male and one female. And while the female's nipples were quite prominent, especially after giving birth, I don't remember the male having any nipples at all. Do ...
5
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1answer
195 views

Why was polyploidy not lethal in certain octodontid rodents?

As discussed in Why is polyploidy lethal for some organisms while for others is not?, polyploidy is normally lethal in mammals. However, two species of Octodontidae (South American rodents), are ...
6
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3answers
108 views

laboratory mice, nutrition, and humans

It seems that many nutrition experiments [directed at human diet] are carried on laboratory mice. Is there any justification that nutrition that is good or bad for laboratory mice will also be same ...