By Alice Klein.
A male Jackson's chameleon is from Hawaii.
Holland is named Brenden.
Half a century after being introduced to Hawaii, the Kenyan chameleons have evolved into flashier colors.
Jackson's chameleons are native to Kenya and change colour depending on their context.
Males turn yellow to attract females or to signal their dominance to other males. At times, they switch to green and brown to blend in with the vegetation and avoid being seen by birds and snakes.
A pet shop owner in Hawaii imported about 36 Jackson's chameleons in 1972. They escaped when he placed them in his garden. Hawaii has few animals that can prey on them, so they were able to establish themselves.
Martin and his colleagues wondered if being released from the pressure of the predator led to changes in the colour of the animal.
They used Jackson's chameleons from Hawaii andKenya to test this. They exposed each individual to another male, female, model bird and snake, and observed their colour changes in response.
The yellow of the Hawaiians was 30 per cent brighter than that of the Kenyans when they encountered another male or female.
The Hawaiian chameleons did a better job of blend in to their environment when exposed to the bird and snake models.
The Hawaiians are probably worse at camouflaging themselves since they no longer need to.
The brighter yellow displays of the chameleons may have evolved to increase their chances of attracting mates and reproducing, he says.
It has happened in 50 to 65 generations, which is pretty quick.
lizards can evolve longer legs within six months after being introduced to new islands, according to other studies.
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