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Photo Credit: Jörgen Wiklund |
Only males among the fish species crucian carp have developed a strategy to protect themselves from hungry predators, according to a new study from Lund University in Sweden. The explanation could lie in that the surrounding environment affects the stress system in males and females differently.
Some animals have evolved the ability to swiftly change appearance to defend themselves against predators when necessary - while avoiding the unnecessary costs of that appearance when it is not needed. This is an advantage for animals that live in environments where the risk of being eaten by predators varies. However, there is a difference in the ability of females and males to escape the enemy in this way. Researchers at Lund University have investigated the crucian carp fish species.
“When the smell of predatory fish spreads in the water, the male crucian carp begins to change its appearance, much like a character from Transformers. From having grown in length, the presence of the predatory fish causes the male carp to instead grow in height. The new body shape makes it much more difficult for gape-size limited predators to swallow them. The shape also provides better acceleration, which is an advantage when the fish has to escape from an attacking pike”, explains Jerker Vinterstare, biologist at Lund University.