The biological study of animals.

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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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118 views

How was the cama's life expectancy computed?

A cama is a hybrid between a male dromedary camel and a female llama. The first cama was born on January 14, 1998, yet on the Wikipedia page it is said that a cama's life span is 30–40 years. How was ...
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280 views

Do animals exist which have great vision, but see only grayscale?

In computer vision the color information is often discarded, as most object recognition tasks seem to work just as well on the greyscale image (even better, because there is less unnecessary ...
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107 views

Why are plants classified in living things? [closed]

@Volunteers Beware that I am none of the biological magnates. Nor a philosopher. This is just a sign of curiosity. And, I want only an intuition that enables me to see the difference. As far as I ...
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2k views

Does cockroach lay eggs in human flesh when they “bite”?

Recently, i have "bite" by cockroach, not only the "bitten" area red and swallowing, and more specificly, it have a big hole in that area, when i clean it with hydrogen peroxide solution, something is ...
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58 views

Which Darwin book (and today edition) is illustrated by his own drawings?

I am interested in buying Charles Darwin books and mostly drawings (nowadays editions, I am not a collector). Please, can you advise in which book and which edition I can find the most of his ...
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32 views

Locomotion of Hydra: Why Somersaulting is better than Loop locomotion when moving to a larger distance?

In my text I read about different types of locomotion of Hydra where I learnt that generally Hydra moves by somersaulting and it is faster than 'Loop locomotion' which Hydra uses for moving to a large ...
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Why is it called Nematocyst “Battery”?

I was reading an article on Hydra where they mentioned Nematocyst Battery. I know that Hydra and other Cnidarians have nematocyst but why are they called Nematocyst 'Battery'?
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271 views

How did zootoxins evolve?

I've always wondered how toxins in certain organisms have evolved. Particularly, organisms that produce toxins as a deterrent to predators as opposed to organisms that use it to paralyze their prey. ...
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286 views

Was the recent “conservation hunt” of a black rhino supported by science?

CNN recently covered a sanctioned black rhino hunt in Namibia by Texan Corey Knowlton, who bid US$350,000 for the license. In the story, he claims that the hunt was actually supporting conservation of ...
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12 views

Are there more efficient forms of sleep among mammals?

We know that there are 4 distinct sleep stages among humans and we need about 5 sleep cycles each night. With this in mind, are there mammals that achieve their sleep needs more efficiently? I'm ...
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334 views

Is there any documented evidence for suicide among vertebrates other than humans?

Is there any documented evidence for suicide among vertebrates other than humans? Lemmings not accepted !
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28 views

Why are compost worms sensitive to light?

I read that compost worms dislike light. But I'd say they don't have eyes and I couldn't imagine their skin is sensitive to light in general, is it? And if so, then why?
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159 views

Are there animal species with sex of an offspring determined by sex of preceding offspring?

For instance, if an animal's first offspring is male, then all subsequent offsprings will be male too (the sex of first offspring could be determined randomly). Does it happen in any species?
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small cocooned caterpillar found on bathroom door - what is this creature?

This larvae / moth has what seems to be a smooth gray cocoon which looks like a piece of cement. It can carry this cocoon with it as it crawls, and it can come out from both ends of this cocoon. ...
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13 views

what is the role of gills in terrestrial crustaceans?

I would like to know why do crustaceans that live on land have gills. I know that gills play pivotial role in respiration, but terrestrial crustaceans use tracheal lungs.
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24 views

Can immortality of the Turritopsis dohrnii be learned or adapted by other species?

I have heard that Turritopsis dohrnii is a species of jelly fish which is immortal, as it can grow old and then back to growing young. So, how is it possible? Can other species (marine and/or land) ...
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1answer
115 views

Unknown animal - What could it be?

It's the first time I use this website and I really need help because I'm totally stuck Now I'm in school, but I'm trying to prepare for the Olympics During the preparation, I found the issue on the ...
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2answers
1k views

What is a group of tortoises called?

This post at Mental Floss stated that a group of tortoises is called a 'Creep'. I had never heard of that before, and in trying to find the references for the name, I was surprised that I couldn't ...
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195 views

Examples of prey predator interactions where density of predator is very low and prey form groups when the predator attacks the prey for food

Examples of prey predator interactions where density of predator is very low (has a threat of extinction) and prey form groups when the predator attacks the prey for food. I have searched this ...
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304 views

Why would villagers attack Orangutans?

I read today in the news that villagers in Borneo were attacking refugee Orangutans. Why would they do this?
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24 views

Which metazoans host anaerobes to aid in digestion? Do any host oxic digestive tracts?

Many metazoans (e.g., mammals, insects, earthworms) have anoxic digestive tracts that are colonized by anaerobic microbes that perform portions of digestion of food for the host. Some other metazoans ...
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23 views

Is pathlength correction vital to be included while quantifying protein

I am trying to quantify protein in serum/plasma samples. I have carried out biuret assay for my samples using microplate reader. While performing I encountered the doubt whether I should include ...
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37 views

What do “reduced antipredator defense” and “reduced antipredator vigilance” mean?

I encountered the terms "reduced antipredator defense" and "reduced antipredator vigilance" in this book Can you help me to make sense of these terms?
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Do other primates get gallstones?

Which non-human primates actually get gall stones the same as humans? All, some, none? References appreciated! Anecdotes about pet primates with gallstones also welcome if you have any...
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37 views

Identification of this species of Toad

I found a short -- 20 second/s -- video on the Internet of a toad and I wonder if anybody could identify it? Here is the hyperlink; http://weloveshortvideos.com/post/132047898162 It was posted on a ...
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2answers
298 views

Why do snails come out after the rain?

Many times, when there is rain after a long time, snails come out afterwards, and you can see snails and slugs everywhere! I have two questions: Why do they come out after the rain? Where are they ...
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Steppe peoples method for healing horses' wounds

There was a custom among nomadic steppe peoples like Huns or Mongols of putting pieces of saltened meat in wounds of their horses to make them heal faster. Did it work? If so, how? I suppose it has ...
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2k views

Why do men have nipples?

I'd be tempted to call nipples in men vestigial, but that suggests they have no modern function. They do have a function, of course, but only in women. So why do men (and all male mammals) have them? ...
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39 views

How can birds keep their eyes moist during flight? [duplicate]

Mammals have an upper lid and small mass of tissue in the upper corner known as nictitating membrane. This helps keep the eyes clean; birds can moisten their eyes in flight using this membrane ...
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67 views

Which class of animals constitute the largest biomass?

I found here that species-wise it is cow. But, collectively, insects may exceed even mammals. So, which class of animals constitutes the largest biomass?
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1answer
96 views

Please identify organ

This is the gut area of an Eastern Grey Kangaroo taken of a property in the Southern Highlands of NSW, Australia. The top red organ appears to be the spleen but what is the elongated tubular organ ...
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966 views

Do all sea creatures that have scales have to have fins?

Do all sea creatures that have scales have to have fins? Do we know of any sea creatures that have only scales without fins? I'm especially interested in fish that have scales but no fins.
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Why do some animals have 8 Limbs (e.g. Spiders, Octopuses)?

Octopuses have 8 tentacles, spiders have 8 legs. Is there something special about 8? It seems like an animal that needs 360° mobility has 8 legs.
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Why are lions the only social cats?

We know that almost all cats are solitary. How did the Lions (Panthera leo) end up social animals? Do we have an explanatory evolutionary path describing how the Lions became social while the rest of ...
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2answers
353 views

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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Is lung size/shape a factor in long-continuous running of animals?

Apart from other factors, does lung shape/structure/size play any role in long-continuous running animals. Is there any similarity in lung structure between different long-continuous running species? ...
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561 views

What is the known maximum ranging distance of a bat's sonar?

Bats are known to navigate by using echo-location. How far away can a bat detect an object by its sonar?
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Are there fishes with a double circulatory system?

Our courseware materials say there are such fishes, but my Internet searches suggests fishes only have a single circulatory system.
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367 views

What kind of bird species is this?

Every now and then I got a glimpse of this bird which I'm pretty sure is not native to Northern Germany where I live. There are at least three of these birds around but I usually only see something ...
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374 views

Why Egg shell is not called a cell wall?

Egg is a single cell and has a outer hard covering outside inside which there is a cell membrane. Then why isn't the egg shell a cell wall? Is it because no exchange of materials take place through ...
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74 views

The biggest underground living animal

It's easy to find informations about the biggest animals at land / at sea / in the air. But what was the biggest animal that ever existed, that lives underground? No animals that were forced to live ...
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1answer
5k 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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is a musk deer's musk pod in its abdomen, its back, or its bottom/rear end?

I have read/heard different things about where a musk deer stores its perfume Some links say it stores it in its abdomen just in front of its penis. Others say the rectum(by which I suppose they ...
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Was this snake behaving abnormally?

This morning, I walked out front of my house to find a medium-sized snake balled up on my driveway beneath my motorcycle. I spotted it from my porch so I didn't walk any closer. I believe it was a ...
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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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44 views

Biological Evolution outside of Earth [closed]

What drives evolution forward? I heard that climate change drives species to evolve and adapt. Is there any other mechanism that is encoded in our DNA by which species can over abrupt changes, evolve ...
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1answer
25 views

Endothermy in different species

Birds and mammals are both endothermic, meaning they metabolically generate the heat they need to keep their body within a certain temperature ranger. But birds are closer relatives to reptiles than ...
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Why do I often see male robins with female robins?

Even when it is not breeding season for robins I still often see male robins with female robins. But why? I know that the male robin often chirps to find female robins within his territory. I also ...
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Do any predatorial animals attempt to appear smaller?

There are many animals that have behaviors or characteristics to make themselves appear larger than they are as a defense mechanism, such as butterflies have large eye patterns on their wings. Are ...