Questions related to mammals.

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Is there a relationship to hibernation, metabolically stymied life… and lifespan? [on hold]

This photo of an insect is in what I can assume is metabolic stasis, for lack of a better word .... it seems to be "hibernating". Question Is there a relationship between hibernation and this ...
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1answer
89 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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0answers
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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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44 views

Can Kit fox and Red fox 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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11 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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0answers
38 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
28 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
76 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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1answer
357 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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1answer
44 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
38 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
50 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
205 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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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 ...
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1answer
76 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
32 views

How do I get recombinant proteins into the nucleus of mammal cells?

I know that there are Nuclear Localisation Sequencenes (NLS). They can be taken from endogenous or viral proteins and fused to the N or C terminus of my recombinant protein. Which is the best one? ...
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1answer
58 views

What is the evolutionary purpose of white spots in nails and how can they be characterised due to Leukonychia? [closed]

Suppose you haven't hit your nails so the white spots are due to Leukonychia. Are the discoloration i.e. the white spots due to lower porosity (less minerals absorbing) or some other factor? I ...
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2answers
169 views

Why only female mammals have well developed mammary glands?

In course of evolution (possibly), mammary glands became vestigial in male mammals, but became fully developed in females. Is there any plausible explanation for this characteristic?
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25 views

Are there any mammals whose males can feed with milk? [duplicate]

Are there any mammals whose males can feed the offsprings with milk from the breasts?
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1answer
52 views

How to determine externally that a whale is a mammal?

Mammals have external qualifying characteristics like body hair, ear pinna, etc. But a whale has none of that. So, can it be identified as a mammal just by external observations?
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27 views

Which agricultural crops attract rodents?

Are there any data on rodent populations per acre of different types of agricultural crops?
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1answer
54 views

What does it mean for the signals for transcription and translation to be “conserved”?

I was reading this article: "Overview of vector design for mammalian gene expression." for an explanation of why mammalian cell lines are used for expressing cloned genes, and one of the reasons ...
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2answers
509 views

How do marine mammals control buoyancy?

Presumably, as a whale or seal dives, its lungs get compressed by the increasing water pressure, and it gets less buoyant. Under this model, for a given amount of air taken in at the surface, the ...
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1answer
59 views

About the plight of Elephants and efforts to conserve them? [closed]

Poachers are only after the ivory horns right? I read this story from the New York Times ( I think) of saving a Rhinocerous by some Park Rangers and a Vet. ( forgive spelling) ; they tranquilized the ...
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40 views

Why does a pecking order almost always exist in groups of social mammals?

I think the best explanation might come from evolutionary game theory. But, an another viewpoint may be equally important.
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4answers
7k 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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2answers
3k 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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2answers
194 views

Why does botulinum toxin seem to be more dangerous to humans than to other mammals?

Various mammals seem to get away with eating parts of carcasses that we would prefer to not even touch, and that we assume will make us sick. Because of that, I assume botulinum toxin is more ...
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1answer
109 views

Why are recombination rates increasing in mammals?

I have recently become fascinated with an awesome topic in biology and evolution that I feel is rarely covered in biology courses. That is, rates of meiotic recombination, or the the amount that an ...
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1answer
165 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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1answer
31 views

Book recommendation on mammal (or just primate) behaviour, especially in relation to child-rearing

I have a growing frustration with the lows 'new-age' parenting is reaching, along with asininity of so much of our public schools' (and summer camps') philosophies and policies in relation to our ...
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1answer
101 views

Has any creature ever devolved to be cold blooded? [closed]

Is this even possible? Because I have a non-scientific gut feeling that it is irreversible. Whales and dolphins are evolved from land mammals, and they've remained warm blooded while it doesn't give ...
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1answer
194 views

What species is this mammal?

I saw a mammal that looked like a large squirrel. I haven't seen anything quite like it. Can you help me identify it? Squirrel-like, "hunched over" posture. It was too large to be an eastern ...
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0answers
64 views

How important is the womb's environment?

- Background - Talking about one phenotypic trait, the total phenotypic variance $V_p$ is decomposed into genetic and environmental variance for this trait, represented by the symbols $V_G$ and $V_E$ ...
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2answers
307 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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2answers
310 views

Does Science Say That We Should Die? [duplicate]

Excluding situations where you die from accidents, the main reason for death is -generaly- diseases. And usually it is about an organ which becomes "tired" after many years. These results are all ...
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1answer
42 views

In what circumstances does a mammalian egg copy its DNA?

In the 2nd episode of the new Cosmos series, the host Neil deGrasse Tyson shows how the white-furred bear could have evolved (reasonable scientific speculation, of course). If you haven't seen that ...
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1answer
351 views

Are females more flexible than males in all mammals?

It's common that human females have a more flexible body than males, (but I don't know why, so it'd be helpful if someone answers why so as well!) but does this apply to all mammals?
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1answer
87 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 ...
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2answers
445 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 ...
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1answer
58 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
79 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
3k 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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5answers
2k 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
66 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 ...
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3answers
644 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
542 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?
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1answer
397 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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1answer
162 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 ...