Sharks has caused stress in sea lions
Marine biologists have studied the effect of the presence of predators on the level of stress the seals. In an article published in the journal Ecology reported that animals living in areas with great white sharks, are subject to greater stress than their relatives living in safer places.
Stress is a standard defensive reaction of a living organism on exposure to unpleasant factors (physical or psychological) from the environment. Although this reaction plays an important role in survival (for example, in a state of “fight or flight”), prolonged exposure to stress can negatively affect mental and physical health: for example, lead to sleep disorders.
Among the sea creatures stress has a big impact on survival: for example, living in captivity of the southern fur seals are more likely to suffer from cardiomyopathy.
In the new work, the biologists led by Scott Creel (Scott Creel) from Montana state University, tested the impact on the level of stress another important factor is the number of predators on-site habitat.
To do this, scientists during the three years studied six colonies of Cape fur seals (Arctocephalus pusillus pusillus) on the coast of South Africa. The main predators that threaten animals are the white shark (Carcharodon carcharias), also common in the area. The researchers were equipped with a 37 white sharks on the studied territories GPS trackers to track their position during the observation time.