Alrighty then! How formal do blogs have to be? I dont think Tumblr is that highly regarded in the scientific community, so lets give this a crack hey team, and attempt to make it mildly entertaining.
So I had a bit of a squiz at this scienctific report on the breeding cycle of the Australian Seal Lion (neophoca cinera), clearly one of the coolest animals out.
http://www.nrcresearchpress.com/doi/abs/10.1139/z93-290
Aussie Sea Lions (ASL) are apart of the pinniped family which encompasses true seals (leopards seals, elephant seals ect), eared seals ( sea lions and fur seals ) and their fuller figured cousins, the walrus. Of the 33 species in the pinniped family, only two species don't reproduce on a fairly dependable annual cycle, the Australian Sea Lion and the Walrus ( Odobenus rosmarus ).
Raising a ASL pup is a very time costly venture with a vast range of data collected on how long mothers will nurse their pup. Most mothers will nurse their young right up until one month before giving birth to the next pup. From birth to weaning generally takes 15- 18 months, however some mothers nursed for up to 40 months before issuing the eviction notice. By then the pup is almost 4 years old! That's almost full grown. Now imagine that in humans. Bit creepy. Gestation last 17.6 months, most with a nursing pup the whole time. Only 71 reproduced on an 18 month breeding cycle.
As with most scientific reports, much to my disappointment, it lacks visual imagery (aka pretty pictures) so here's one for you.
Interesting. Pretty pictures are always a plus! I’m curious how this relates to menopause and menstruation? You mention cycling, but many female mammals show an oestrous cycle. How does this compare to menopause and menstruation, which isn’t well known in animals, outside of humans?
ReplyDeleteCool post Scott! Sea Lions are totally majestic I agree!! Just a quick question as to whether there has been any research into why these ASL mothers have adapted the behaviour to nurse their pups for so much longer than other pinniped family members?
ReplyDeleteWhy yes Jac, what a valid question. ASL spend far less time with their young hauled out on beaches feeding, initially, ASL will stay with their young for 9 days without mum feeding, where as nearly all other pinnipeds will stay with their young for up to a month. The ASL will haul out for only 30 hours to feed their pup, then spend up to 48 hours at sea hunting. Other pinnepeds will hunt for less and spend more time with their pups, allowing them to grow faster, and wean earlier.
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