Pregnant elephant seals have a “built-in GPS” that tells them exactly when to return to a 6,200-mile journey home from feeding places just in time to give birth, according to a study
- Every year, pregnant female seals travel thousands of miles in search of food
- However, they always return to their home beach in time to give birth
- Researchers have used satellite data to track more than 100 seals during their voyage
- The data revealed that the seals decide to turn strongly based on how far they are from where they should go
Each year, pregnant female elephant seals make an ambitious 6,200 miles (10,000 km), 240-day journey across the Northeast Pacific in search of food.
However, it seems that females always return home just in time to give birth – and it is still unclear how they manage to choose this moment.
Now a new study has revealed that pregnant females appear to have an inner sense of the map, which functions as a built-in GPS and helps ensure they return home within five days of their puppy’s arrival.
“Migratory seal elephants know how far they are from their beach to breed thousands of miles,” said Roxana Beltran of the University of California Santa Cruz.
“They also know approximately how long it will take them to return.”
New research reveals that pregnant females appear to have an inner sense of the map, which functions as a built-in GPS and helps ensure they return home within five days of their puppy’s arrival.
Each year, pregnant elephants make an ambitious 6,200 miles (10,000 km) 240-day journey across the Northeast Pacific in search of food. However, females always seem to return home just in time to give birth. The lines shown are their travels, with the yellow dots indicating the point at which each seal turned
Elephant seal migrations
Elephant seals migrate in search of food, spend months at sea and often dive deep to feed.
They return to their beds in the winter to reproduce and give birth.
Although both male and female elephant seals spend time at sea, their migration routes and feeding habits differ: males follow a more consistent route, while females change routes in pursuit of moving prey.
In the study, the team used satellite tracking data to track more than 100 adult female elephant seals as they traveled across the Northeast Pacific.
This allowed them to know exactly when each seal turned to return to its home beach.
The data revealed that the seals decided to turn strongly based on how far they were from where they should go.
However, their decisions to turn are not related to their physical condition – measured as the amount of body fat.
“We were surprised that the success of the search for food or the percentage of body fat was not more strongly related to when the seals begin the return part of the migration,” said Ms. Beltran.
“We expected very successful (ie, thicker) seals to end their forage trips earlier, but that was not the case; instead, they appear to be well-programmed to turn strategically based on where they are and in turn how long it will take them to return. ”
It is still unclear what sensory evidence the animals rely on to track their whereabouts and head in the right direction for home.
In the study, the team used satellite tracking data to track more than 100 adult female elephant seals as they traveled across the Northeast Pacific. This allowed them to know exactly when each seal turned to return to its home beach.
The data revealed that the seals decided to turn strongly based on how far they were from where they should go. Their decisions to reverse are not related to their body condition – measured as the amount of body fat
However, according to researchers, it is clear that they can adjust their travel time based on this “internal GPS”.
The team hopes their findings will improve our understanding of elephant seals, with important implications for their conservation.
In future studies, they hope to determine exactly how accurate the seal’s navigational ability is and determine which signs are most important.
Share or comment on this article: