Viewing the revival of extinct species as a laboratory exercise overlooks key behavioural and ecological factors that cannot easily be reproduced (S. Kumar Nature 492, 9; 2012). Hence a recreated dodo might look and feel like one — but it wouldn't quite be a dodo.

Also, re-establishing an extinct species would mean following procedures that are normally used to introduce captive-bred animals to the wild. However, these repopulation attempts have contributed only marginally to biodiversity conservation, largely because the animals do not know how to interact with other members of their species or with their new environment.

Extant species can be trained on the basis of what we have learned from wild individuals, but such information is sparse or non-existent for extinct species. In the absence of their proper ecological niche, 'revived' species reintroduced into the wild would be unlikely to survive.