Myrmecophaga tridactyla, Linnaeus, 1758

Russell A. Mittermeier & Don E. Wilson, 2018, Myrmecophagidae, Handbook of the Mammals of the World – Volume 8 Insectivores, Sloths and Colugos, Barcelona: Lynx Edicions, pp. 88-90 : 88-89

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Giant Anteater

Myrmecophaga tridactyla

French: Tamanoir / German: GroRer Ameisenbar / Spanish: Oso hormiguero gigante

Other common names: Ant Bear, Great Anteater

Taxonomy. Myrmecophaga tridactyla Lin- naeus, 1758 ,

“in America meridionali.”

Restricted by O. Thomas in 1901 to Per-

nambuco State, Brazil.

Subspecific recognition is based on geographical distributions, but a rigorous analysis of morphology and genetics has not been conducted. Three subspecies recognized.

Subspecies and Distribution.

M.t.tridactylaLinnaeus,1758—SouthAmerica,EoftheAndes.

M.t.artataOsgood,1912—NEColombiaandNWVenezuela,WoftheAndes.

M. t. centralis Lyon, 1906 — from Honduras throughout most of Central America to W Colombia and NWEcuador.

Descriptive notes. Head-body 1000-1400 mm, tail 600-900 mm, ear 35-60 mm, hindfoot 140-180 mm; weight 22-45 kg. Giant Anteaters are the largest anteater species. There is no outward sexual dimorphism. Skull has an extreme degree ofrostral elongation. Tongue (c.600 mm) is slender, worm-like, and as long as head. Muzzle has little, delicate bristles on lips and nose. Circular mouth is toothless. Small ears are rounded; eyes are small. Body is covered with coarse hair, and flanks have triangular chevron enclosed by white line extending to chest and throat. Coat color varies from light to dark gray or brown to grizzled. Hindhead hairs form dense mane. Forelegs are strong and white to yellowish; black bandoffur can be present at height ofcarpus. Black circular spot sometimes occurs at elbow. Forefeet have four digits. First digit is smallest; second and third have prominent, long, powerful digging claws; and the other two digits are reduced. To protect itself from claws, Giant Anteaters walk on their knuckles. Plantigrade hindfeet have five short claws. Tail is non-prehensile, almost the same length as body, and covered with long and brushyhair. Chromosomal complement is 2n = 60, FN = 104.

Habitat. Remarkable diversity of habitats such as grasslands, shrublands, wetlands, tropical moist forests, dry forests, dense forests, hygrophilous forest, Chaco, and savanna. The Giant Anteater also occurs in human-altered landscapes such as soybean plantations near Emas National Park, central Brazil; timber plantations of Acacia sp. (Fabaceae) and Eucalyptus sp. (Myrtaceae) and improved pastures in Colombia and central Brazil. Nevertheless, a recent study of habitat selection found that Giant Anteaters are not able to persist in areas with only modified habitat. Habitat preferences are based on potential of habitat to provide thermal protection. In the Brazilian Pantanal, Giant Anteaters avoided forests and selected open savannas when active, but forested areas were used to rest. In Argentina where climate was cooler, forests were selected.

Food and Feeding. Giant Anteaters consumed more ants than termites in Venezuelan Llanos, Brazilian Pantanal, and Argentina. At least one-halfof the diet contained termites in Serra da Canastra and Emas national parks in central Brazil and Colombia. Giant Anteaters are opportunistic myrmecophagous feeders. Ants in genera Camponotus, Solenopsis, and Pheidole and Nasutitermes termites were most often eaten. Theyalso eat unusual items such as Blattodea eggs, fragments, and larvae of Coleoptera, and western honey bees (Apis mellifera) that maintain their colonies in termite mounds. Foraging is their main activity, and they can ingest thousands of ants and termites per day.

Breeding. During courtship, the female Giant Anteater raises her tail continually and allows the male to be close behind her. Sometimes the male touches or sniffs the female; sometimes they are aggressive toward each other. This behavior can last several days, and the female may have a vaginal discharge. Mating occurs when the female lies on herside, and the male copulates with her while lying next to her. Sex ratio tends to be slightly male-biased. Males and females become reproductively active at 1-8-4 years of age. Estrus occurs year-round, and the cycle is shorter in nulliparous (c.48 days) than multiparous females (c.63 days). Gestation lasts 171-190 days, pregnancies result in single young, andfemales return to estrus after parturition. Neonates weigh c.1 kg; head-body and tail lengths are 330 mm and 530 mm, respectively. Maternal care includes grooming and play, and mothers carry their young on their backs for several months after birth. Until the third month, young feed only on breast milk; they learn to eat solid food after that. Mothers begin to repel young at 8-9 months ofage, leading to their independence. Longevity can be 30 years in captivity.

Activity patterns. Giant Anteaters are terrestrial, but they can climb on termite mounds andintrees in the wild and on walls and enclosure trees in captivity. Wild Giant Anteaters can be active 8-9 hours/day. Activity occurs at any time of the day, and nocturnal activity mostly occurs when persecuted or when human activity is high. Activity periods

can depend on prey availability, anthropogenic impacts, and daily temperatures. In the Llanos of Venezuela, nocturnal activity is related to the nocturnal activity of carpenter ants (Camponotus). In Serra da Canastra National Park and Brazilian Pantanal, activity is affected by daily temperature. In Sao Paulo, the most populousstate of Brazil, Giant Anteaters were active (19:00-05:00 h) when humans were not (08:00-17:00 h), which also occurred at a study site near the capital of the Roraima State in Brazil. They can swim cross large rivers, and bathing behavior is also reported.

Movements, Home range and Social organization. Giant Anteaters move great distances to obtain enough energy from their low-caloric diet. Average daily movement of a Giant Anteater is 3-7 km/day (range 1-3-11 km/day). Home ranges of Giant Anteaters usually have patches of forest, open areas, and habitats related to water (stream, lake, and lagoon). Home range sizes differ among localities because of ambient temperature, seasonality, and density. Home ranges average 5 km? males have larger home range sizes than females; and overlap occurs between and within sexes. Densities are 0-1-2-9 ind/km?, lowest in southern Brazil and the Brazilian Pantanal and highest near Acacia plantations in Amazon savanna in northern of Brazil. Giant Anteaters are solitary, except during courtship and mating and when females raise young. Agonistic encounters are mostly ritualized, involving behavioral postures, such as pawing,circling, roaring, and chasing. Extreme agonistic behavior involves standing bipedally and displaying claws.

Status and Conservation. CITES Appendix II. Classified as Vulnerable on The IUCN Red List. The overall population of Giant Anteaters is estimated to have declined at least 30% over the past ten years. In some parts of Central America, it is considered the most threatened mammal species, and it has disappeared from Belize and Guatemala. In the southern part of its distribution, there is a pattern of population decline; it is considered to be extinct in Uruguay and threatened in several states of Brazil: Espirito Santo and Rio de Janeiro (extinct), Sao Paulo (vulnerable), and Parana, Rio Grande do Sul (critically endangered). Population declines are due to habitat loss and alteration, wildfires, road kills, poaching, conflicts with dogs, and impacts of pesticides. Five Giant Anteaters found dead in a managed forest probably died from exposure to chemical agents used to control ants. Giant Anteaters are eaten by humans, and other uses include making leather, medicine, and ornaments from their skins. Some conservation programs exist in Brazil, Colombia, and Argentina; one of them successfully reintroduced Giant Anteaters in Ibera Wetlands (Argentina).

Bibliography. Aguiar & Fonseca (2008), Alves et al. (2016), Bertassoni et al. (2017), Braga (2010), Braga et al. (2014), Camilo-Alves & Mourao (2006), Chiquito & Percequillo (2009), Collevatti et al. (2007), Di Blanco et al. (2017), Drumond (1992), Emmons (1990), Fallabrino & Castineira (2006), Gallo et al. (2017), Gardner (2008), IAP (2010), Knott et al. (2013), Kreutz et al. (2012), Macedo et al. (2010), Marques et al. (2002), McNab (1984), Medri et al. (2003), Miranda, FR. et al. (2015), Miranda, G.H.B. (2004), Miranda, J.F. & Bertassoni (2014), Montgomery (1985¢), Montgomery & Lubin (1977), Morford & Meyers (2003), Mourao & Medri (2007), Naples (1999), Passos et al. (2017), Patzl et al. (1998), Redford (1985b), Rojano, Lépez et al. (2015), Rojano, Miranda & Avila (2015), Sandoval-Gémez et al. (2012), Shaw, Carter & Machado-Neto (1985), Shaw, Machado-Neto & Carter (1987), Superina et al. (2010), Svartman (2012), Thomas (1901a), Timo et al. (2015), Tortato & Althoff (2011), del Valle & Halloy (2003), Versiani (2016), Vynne et al. (2011), Wetzel (1982).

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Plate 3 Species Accounts

Subspecies and Distribution. M.t.tridactylaLinnaeus,1758—SouthAmerica,EoftheAndes. M.t.artataOsgood,1912—NEColombiaandNWVenezuela,WoftheAndes. M. t. centralis Lyon, 1906 — from Honduras throughout most of Central America to W Colombia and NWEcuador.