However, it has been reported that rhesus monkeys exhibit other behaviours in response to a mirror that indicate self-recognition. Rhesus macaques have been observed to use mirrors to study otherwise-hidden parts of their bodies, such as their genitals and implants in their heads. It has been suggested this demonstrates at least a partial self-awareness, although this is disputed. Black-and-white colobus (Colobus guereza) Capuchin monkey (Cebus apella) Hamadryas baboon (Papio hamadryas) Cotton-top tamarin (Saguinus oedipus) Birds Grey parrot New Caledonian crow Jackdaw Great tit (Parus major) Fish The Tanganyikan cichlid, or daffodil cichlid (Neolamprologus pulcher), is another fish that has failed the mirror test, according to a study done in 2017. Although not cleaner fish like the cleaner wrasses, these fish are typically regarded as socially intelligent and can recognize conspecifics in their social groups. Therefore, they would theoretically make good candidates for the mirror test, but they ended up failing. Similar to the cleaner wrasse, the Tanganyikan cichlid first exhibited signs of aggression towards the mirrored image. After a colored mark was injected, the researchers found no increased scraping or trying to remove the mark, and the cichlids did not observe the side with the mark any longer than it would have otherwise. This demonstrates a lack of contingency checking and means that the Tanganyikan cichlid did not pass the mirror test. Cephalopods Octopuses oriented towards their image in a mirror, but no difference in their behaviour (as observed by humans) was seen in this condition when compared with a view of other octopuses. Animals that may pass Mammals Primates Gibbon (g. Hylobates, Symphalangus and Nomascus) have failed to show self-recognition in at least two tests. However, modified mirror tests with three species of gibbons (Hylobates syndactylus, H. gabriellae, H. leucogenys) in 2000 showed convincing evidence of self-recognition even though the animals failed the standard version of the mirror test. Another study published in 2009 documents 12 cases of spontaneous self-recognition in front of the mirror by a pair of siamangs (Symphalangus syndactylus). Pigs Pigs can use visual information seen in a mirror to find food, and show evidence of self-recognition when presented with their reflections. In a 2009 experiment, seven of the eight pigs tested were able to find a bowl of food hidden behind a wall and revealed using a mirror. The eighth pig looked behind the mirror for the food. BBC Earth also showed the food bowl