why do some animals, such as salmon, and octopi, die after they lay eggs? specifically, what do they die of?

Question

ok but what about octopi? they hang out being adult for like 3-7 months, lay eggs, and die... is their life span just that short, or, if they did not lay eggs, would they continue to live?

Answer 1

Nature has a cruel sense of humor sometimes. There are many animals that die soon after laying eggs. The primary cause is multiple system failure. The organs of the animal just shut down. Whether this is due to old age or just genetically determined is unclear. The advantage, evolutionarily, is that when the adult dies the offspring have less competition when they hatch.

Answer 2

I don't know about octopi, but salmon are built to spawn at the very end of their life cycle. They basically beat themselves to death swimming upstream to their spawning grounds; they are physically in awful shape by the time they get there and the act of digging a hole for their eggs and covering them up completely finishes them off.

I'm glad it's not like that for people!

Answer 3

They die of exhaustion.

Let's use salmon as an example.

Spawning salmon expend nearly all their energy in the act of spawning. It can take weeks and they don't save anything for the trip back.

But, some salmon do not die. There are fish who have made two or (rarely) three spawning runs and still kept on swimming.

http://animaldiversity.ummz.umich.edu/site/accounts/information/Salmo_salar.html

Answer 4

I haven't done autopsies on them, so I don't know definitely. From what I have heard, salmon die essentially from exhaustion and old age.

Answer 5

A really good time?