Anteaters after the Flood

The Myrmecophagidae includes the extant tamanduas (Tamandua) and the giant anteater (Myrmecophaga), along with the fossil Neotamandua and Protamandua. The two species of tamanduas are semi-arboreal, have prehensile tails, and have normal grasping clawed digits. Tamandua is known from Pleistocene fossils (Hayssen 2011).

Myrmecophaga is monotypic today, M. tridactyla, though at least one Miocene-Pliocene fossil species is known, M. caroloameghinoi (Gaudin et al. 2018). Giant anteaters are large, terrestrial, with a rigid tail, and knuckle-walk on their front clawed digits (Hirschfeld 1976). While they typically engage in plantigrade ‘knuckle-walking’, when disturbed they can rise erect on their hind legs and defend themselves with their powerful claws, with sometimes fatal results to attackers (Haddad, Jr., et al. 2014; Grillo et al. 2022). Giant anteaters are on the extreme end of specialized myrmecophagy, with a highly elongated skull that is toothless and incapable of chewing, and a long, sticky tongue that works through rapid protrusion/retraction. Tamanduas have a similar feeding strategy, while pygmy anteaters are behaviorally similar in feeding while exhibiting biomechanical differences due to dissimilar skull shape and masticatory apparatus (Naples 1999; Ferreira-Cardoso et al. 2020).

Rather than simply tearing apart a termite or ant nest, the giant anteater makes a small breach, focuses on rapidly ingesting the trickle of ants that pour out for a minute or two, then leaves once the soldiers arrive to protect the nest. The anteater moves on to another nest and repeats the process, taking only a small percent of insects from any given nest, and not causing too much damage (Naples 1999). Up to 35,000 ants/termites may be eaten in a day (Gaudin et al. 2018). Giant anteaters are South American, but at least one Pleistocene specimen has been discovered in Sonora, Mexico, demonstrating northward expansion after the Isthmus of Panama connected the two continents (Shaw and McDonald 1987). Pleistocene specimens of the modern species are also known from Brazil and Uruguay (Gaudin et al. 2018).

Protamandua was an early Miocene sister taxon to the other myrmecophagids, with a skull that was elongated similar to the modern Cyclopes and a body length about half the size of modern Tamandua (Bargo et al. 2012). It was likely a good climber, had a prehensile tail (as does Cyclopes and Tamandua), and strong claws for tearing into social insect nests, along with cranial specializations for myrmecophagy. The middle Miocene-Pliocene Neotamandua “is most likely part of an anagenetic line of descent leading to Myrmecophaga” (De Melo Casali et al. 2020). Neotamandua was intermediate in size between Tamandua and Myrmecophaga (Hirshfeld 1976).