91 votes
Accepted

Do animals exhibit handedness (paw-ness?) preference?

Short Answer Yes. handedness (or Behavioral Lateralization) has been documented in numerous vertebrates (mammals, reptiles and birds) as well as invertebrates. This includes domestic cats (see Wells ...
theforestecologist's user avatar
59 votes
Accepted

Why can't we kill ourselves by holding our breath?

Short answer Healthy people cannot hold their breaths until unconsciousness sets in, let alone commit suicide. Background According to Parkes (2005), a normal person cannot even hold their breath to ...
AliceD's user avatar
  • 52.4k
52 votes
Accepted

Does animal blood, esp. human, really have similar salinity as ocean water, and does that prove anything about evolution?

Short answer Early sea water had a very different osmolality than blood plasma. Background The reference range of serum osmolality is 275–295 mosm/kg (mmol/kg) (MedScape). The osmolarity of sea water ...
AliceD's user avatar
  • 52.4k
49 votes
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How long can an octopus survive out of the water?

Short answer Under ideal conditions, an octopus may survive several minutes on land. Background Octopuses have gills and hence are dependent on water for the exchange of oxygen and carbon dioxide. ...
AliceD's user avatar
  • 52.4k
38 votes

Why do wasps have "wasp waists"? What's been optimized?

Why do humans have such a flexible shoulder? Our ancestors relied on throwing things so the ones who could throw things better did better. What is the wasp's equivalent weapon? The stinger. Wasps ...
Jeremiah's user avatar
  • 831
36 votes
Accepted

What is the human energy consumption by organ?

Percent of basal metabolic rate by organ (BC Campus Open Education): Liver and spleen : 27% Brain: 19% Skeletal muscle: 18% Kidneys: 10% Heart: 7% Other tissues (lungs, intestine, skin, bone, fat ...
Jan's user avatar
  • 8,059
35 votes

Why can't we kill ourselves by holding our breath?

Counterexample: At least some people can train themselves to hold their breath until they pass out, and if this occurs underwater they will almost certainly die by drowning. When I was in military ...
feetwet's user avatar
  • 795
30 votes
Accepted

Why do mints make your mouth feel cold?

The feeling of cold from mints is caused by menthol. Menthol affects the TRPM8 receptor on skin and also in the mouth. TRPM8 is also a general cold receptor: so if you are in contact with menthol the ...
AlexDeLarge's user avatar
  • 2,868
29 votes

Does animal blood, esp. human, really have similar salinity as ocean water, and does that prove anything about evolution?

The argument that blood plasma resembles sea-water, in essence, relies on the notable similarity in concentration of two ions in plasma and sea-water, compared with their intracellular concentration: ...
user338907's user avatar
  • 4,678
29 votes
Accepted

Why do animals excrete excess nitrogen instead of recycling it?

I think your quote more or less explains it: what advantage is there is recycling nitrogen when you're ingesting more than required? Additionally, we recycle nitrogen all the time, especially in amino ...
Bryan Krause's user avatar
  • 45.3k
26 votes

Why is wombat scat (feces) shaped like cubes?

I'm almost certain that your question is based on the press that Patricia J Yang's research is receiving (e.g., here and here). Yang and her co-authors examined the structure and mechanics of some ...
theforestecologist's user avatar
18 votes

Public database of animal specifications

You might be interested in the PanTHERIA database for several thousand mammalian species. It has up to 53 characteristics for each species (but many fields have no entry). It is available as two ...
mgkrebbs's user avatar
  • 9,034
14 votes

Why does the affinity of haemoglobin for oxygen decrease at high altitudes?

The answer to this question is yes, a decrease in oxygen affinity will decrease the oxygen taken up by the haemoglobin (Hb), but it is an appropriate response because it will have a greater effect in ...
David's user avatar
  • 25.2k
14 votes
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Do colour-blind people see white?

It's definitely not white or grey generally, it's a mix of other colors, they often have low resolution of a particular color so that it's less visible rather than visible and grey. Here's a page ...
bandybabboon's user avatar
  • 10.4k
14 votes

Can mosquitoes be attracted by our voice?

Mosquitoes can hear the human voice. If they use human sound to hone in on us as a source of a blood feed is not known at this time, however research into this has just begun. This is especially ...
anongoodnurse's user avatar
13 votes

Public database of animal specifications

I'm not positive, but I assume you'll be hard-pressed to find a list that checks your boxes of needing both multiple metrics for multiple animals. However... Two sources that seem to prove me wrong:...
theforestecologist's user avatar
12 votes

Why are there no organisms with metal body parts, like weapons, bones, and armour? (Or are there?)

https://en.m.wikipedia.org/wiki/Scaly-foot_gastropod Gastropod that incorporates greigite, pyrite, and graphite on it's shell and foot. Due to the large quantities of these compounds in dissolved ...
Loki'sbane9's user avatar
12 votes

Why do I see different hues of colors between each of my eyes?

This is an interesting phenomenon which I have been aware of for several years, but I haven't yet come across any official description of it or explanation for it. Nonetheless, the phenomenon is easy ...
Gwen's user avatar
  • 883
12 votes
Accepted

Why does the affinity of haemoglobin for oxygen decrease at high altitudes?

Haemoglobin's job is to transport oxygen and not store it. Therefore it should also be able to release oxygen effectively. When the differences in partial pressure of oxygen between the tissues and ...
WYSIWYG's user avatar
  • 35.5k
12 votes
Accepted

What's the mechanism for being mentally tired?

There is ongoing research on this topic, but there is a theory known as inhibition theory. It has been defined as: Inhibition theory is based on the basic assumption that during the performance of ...
another 'Homo sapien''s user avatar
11 votes

Pathogens vs Microbes and the Immune System

Not all microorganisms are pathogens Firstly, not all microorganisms are pathogens - some can be harmless and some can be even essential for the host organism functioning (e.g., many microorganisms ...
Roger V.'s user avatar
  • 3,842
10 votes

How long can an octopus survive out of the water?

Found an octopus today which had attached itself to a rock covered in algae during high tide and had failed to swim back out with the receding tide. We found it at low tide, this means it must have ...
Xavi's user avatar
  • 101
10 votes
Accepted

Why is Heart Rate Recovery after exercise reasonably well described by a mono-exponential decay?

I think most people would take exponential decay in a circumstance like this to be the null hypothesis. That is, if you had something not exponential decay, that would be curious and interesting and ...
Bryan Krause's user avatar
  • 45.3k
9 votes

Will you stop sweating if you exercise in a cold enough room?

Apparently you can sweat even in a cold enough room, without even doing exercise! The main causes of sweating include, among exercise and high body temperature, stress and anxiety. This condition is ...
another 'Homo sapien''s user avatar
9 votes
Accepted

Effect of cold showers after intense training

Taking cold showers(10-15 ℃) after training or workout have many benefits: It helps in lowering the damaged tissues temperature by constricting blood vessels. Cold helps numb nerve endings which ...
Mesentery's user avatar
  • 3,275
9 votes
Accepted

Is a one ventricle heart feasible?

Alternative Heart Morphologies Amphibians and some reptiles have a three-chambered heart, with 2 atria and a single ventricle. There are still separate circulatory pathways for the lungs and the rest ...
Bryan Krause's user avatar
  • 45.3k
9 votes

Why is wombat scat (feces) shaped like cubes?

On a more serious note than my comment, and as a supplement to theforestecologist's answer, it's worth pointing out that a cube with rounded corners and edges has larger surface area to volume ratio ...
it's a hire car baby's user avatar
9 votes

What's the benefit of the average human body temperature?

What's the benefit of the average human body temperature? It's a balance between preventing infection and not requiring excessive food intake. It is has also been claimed that this is the temperature ...
Rob's user avatar
  • 393
9 votes

Can mosquitoes be attracted by our voice?

Mosquitos can certainly hear in the range of normal human speech. They are sensitive to the range of around 150-500Hz, and typical human speech is between 100-300Hz depending on your age and sex (DOI: ...
Joe's user avatar
  • 379

Only top scored, non community-wiki answers of a minimum length are eligible