Questions tagged [mammals]

Questions related to mammals, animals that nurse their young, have a neocortex, and three middle ear bones.

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887 views

What was the first animal having fur?

Did all early mammals have fur? Is it possible to trace the origins, how early animals with fur looked like and how it evolved?
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252 views

These Mammals Had a Good Run, So What Happened? [closed]

One of the great mysteries of the mammals is that some of the longest-lasting just aren't with us today. The list of these puzzling unfortunates is as follows: Paleomerycidae DURATION: 55.8 to 4.9 ...
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How do bats manage lymph fluids?

We all know that bats hang upside down to sleep. I was watching some sleep for a while, and they don't move much while asleep. If I fall asleep sitting in a chair my lower legs will swell. Lymph ...
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61 views

What's the best sign language to teach a dolphin?

I know some scientists and trainers used hand signals to communicate with dolphins. The problem is: the dolphins have no hand to express themselves. With chimpanzees, we see how creative they are, not ...
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1answer
279 views

How do marine mammals and penguins maintain bone density?

After much searching on Google with no results, I decided to ask my question here. If I'm not mistaken, swimmers' bone density is less than normal; at least for lifetime swimmers. Astronauts also ...
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1answer
274 views

Identification of a mammal in cage

This unidentified animal was trapped in northern part of Kerala State India and images circulated through social media. Doea anyone know what species this is?
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93 views

Why wrap a dolphin in wet towels?

In this video, a dolphin jumps into a vessel. Even though the guides know they will be quickly helping the dolphin back into the water, they first make sure they wrap the mammal with wet towels. Why ...
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66 views

Why do some macaques have redder faces than others?

I'm watching Monkey Kingdom, and I noticed some of the macaques have redder faces than others. Specifically the females, and as the social ladder increases, so does the redness. An alpha female: ...
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1answer
1k 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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55 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
492 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
131 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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1answer
424 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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34 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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29 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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1answer
410 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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1answer
2k views

How did dolphins acquire their 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? Is it some atavism from eons ago, a ...
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1answer
3k 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
210 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
121 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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1answer
5k 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
142 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
275 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
651 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
2k 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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276 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
3k 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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2answers
19k 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
149 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
133 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 sea)....
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2answers
22k views

How do other primates treat their fingernails?

Do all primates have to trim their fingernails in some way, or do some primates' fingernails wear off through natural use? Also, is constant nail growth common to all primates?
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1answer
263 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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1answer
110 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
773 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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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
659 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
297 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
18k 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 halt ...
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1answer
64 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
304 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
228 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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3answers
10k views

Why have whales and dolphins not evolved to have gills? [duplicate]

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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35 views

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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2answers
172 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
66 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
188 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
2k 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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44 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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2answers
160 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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38 views

Which agricultural crops attract rodents?

Are there any data on rodent populations per acre of different types of agricultural crops?