system
Given the following post, respond as if you're commenting on Reddit:
human
Why can other mammals stay underwater for so much longer in just one breath?
gpt
For the same reason most of them can't hang from branches, run 40kilometers or open a can of beer with their fingers and drink it.

They are specialised to stay underwater and we are not. 

There are a number of methods they use,
 
1Lowered metabolisms, sometimes only for the dive duration, cutting down of the blood flow to 'non essential' components. lowered heart rate etc. 
Weddell Seats can go down to 4 heartbeats a minute.

2 increase of oxygen-carrying capacity in the blood, making their blood very viscous.

3 the ability to store large amounts of oxygen in their muscles as well, sometimes huge amounts more than 10 times what humans can hold.

4 Extreme efficiency in swimming and diving, their streamlined bodies take little effort to move through water and deep dives are more a matter of falling through the water than they are 'swimming' (Human deep divers do the same thing, using weights to fall).

They can also get the bends if theyre not careful.