Dolphins can recognise their own reflections, say researchers in the US. This shows a level of self-awareness never seen before in the animals.
鈥淭his is a very rare ability that up until now has only been shown in humans and great apes,鈥� says researcher Lori Marino of Emory University in Atlanta.
快猫短视频s had thought that close genetic links explained the common 鈥渕irror self-recognition鈥� ability in humans and apes. 鈥淏ut now we鈥檝e shown dolphins recognise themselves in the mirror, we have to contend with the fact that these animals, with very different brains, are arriving at this same rare ability,鈥� says Marino.
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鈥淭his is really striking, because it鈥檚 such a very complex cognitive ability,鈥� she adds.
Marino and colleague Diana Reiss at Columbia University in New York studied two teenage dolphins.
They put a mirror in a small, round pool that was connected to a larger, oval pool by an open gateway. The mirror was positioned just inside the gateway so it could not be seen from the larger pool.
The dolphins were called to the side of the larger pool and either marked with a non-toxic magic marker, or rubbed in the same way with an inkless pen.
The marks were made on the dolphins鈥� heads, fins and bellies 鈥� so they could not see them without looking in the mirror.
鈥淲e found that not only would they make a beeline for the mirror and spend time looking at themselves, but they鈥檇 posture in front of it to expose the marked part of the body to the mirror,鈥� she adds.
If the inkless pen was used, the dolphins would check in the mirror for marks, but move on if they could not see any. 鈥淭here was no training in this and no reward 鈥� this was spontaneous behaviour.鈥�
鈥淪ome people think that if an animal can recognise itself in a mirror, then it鈥檚 capable of other forms of abstract awareness. But we鈥檙e not making that claim, because we鈥檙e not sure that鈥檚 the case,鈥� says Marino.
More at: Proceedings of the National Academy of Sciences (Vol 98, p 5937)