The adult female can be fertilized as soon as she has finished suckling her pup and will give birth to the next one around eleven months later. But the development of the embryo does not commence immediately. The gestation period only lasts seven and a half months in fact. This is known as “embryonic diapause”, which is common in many species of true seals. Once weaned, the young seals gather into groups and progressively enter the water to learn about life in the sea. It is also during this period on land that the young elephant seals lose their natal fur, called lanugo. Some of them can remain on land for three months without eating.

‘’Sentinels of the environment’’

Marine mammals in general and the elephant seal in particular are considered as ‘’sentinels’’ of pollution in the marine environment. The word ‘’sentinel’’ can almost be understood here in its proper sense: a sentinel keeps watch for others; and is the guardian, the look-out who warns others of the presence of danger. Why do scientists consider elephant seals to be sentinels?  Because these animals situated at the top of the trophic networks, are precious bioindicators of the health of the seas. What does this mean? ‘’Perched’’ on top of the food chain proper to their marine environment, they eat mostly fish and squid which have themselves previously eaten smaller fish and crustaceans while the latter have ingested the animalcules of zooplankton a carnivore which is itself a predator of herbivorous zooplankton after the latter has absorbed phytoplankton, itself a predator of the herbivorous zooplankton after absorption of the latter by phytoplankton, the ‘’vegetable soup’’ situated at the bottom of the food chain in the marine environment.