Reptile houses are amongst the most common types of zoo exhibits, with the majority of major U.S. zoos (and I'd presume zoos abroad as well) having some-sort of reptile house. Many of these buildings are historic, but there are also numerous examples of zoos building new reptile houses in recent years. However, when looking at these new reptile houses, one large group of reptiles is suspiciously missing from the display: birds. Phylogenetic and DNA evidence have made it very clear that if reptiles are to be considered a valid, monophyletic group, then birds must be included in this group. However, every zoo reptile house I'm aware of treats them as a paraphyletic group, keeping the non-avian reptiles in a reptile house but no birds. Furthermore, some zoos break these phylogenetic bounds even further- housing amphibians inside reptile houses, instead of giving a distinct exhibit for them (to be fair, at least some zoos are now calling them "Amphibian and Reptile House" to acknowledge that frogs are in fact not reptiles). So really, given that birds phylogenetically fit in the reptile clade, and crocodilians being more closely related to birds than they are to snakes or lizards, then this poses a very serious question about reptile houses in zoos: Despite data showing that birds are in fact reptiles, and accounting for the fact many zoos have built new reptile houses in recent years, why haven't zoos incorporated bird exhibits into reptile houses? Is this only due to differing care requirements, or are there bigger reasons as to why this is true? A reptile house incorporating birds is certainly an exhibit I'd wish to see zoos build in the future, as this is more phylogenetically accurate than excluding birds from the reptile houses.