Giant anteaters (Myrmecophaga tridactyla) are native to the forest and grasslands of Honduras, Brazil and northern Argentina . They are the largest of the four anteater species, weighing 70 to 100 lbs. and measuring five to seven feet from nose to tail. Both male and female giant anteaters are strikingly marked with a black stripe extending from the chest to shoulder. Their fur is stiff and grows long on the tail.
Sadly, giant anteaters are disappearing because of habitat destruction, hunting and road kills. Only about 5,000 anteaters remain in the wild. The International Union for Conservation of Nature (IUCN) lists the giant anteater as vulnerable, although it is considered extinct in areas of Belize, Costa Rica, Guatemala and Uruguay.
Giant Anteater Husbandry Manual
In 2000, giant anteaters Linus and Lucy came to Nashville Zoo from Guyana, marking the first importation of wild-born giant anteaters to a North American zoo in ten years. Fifteen more anteaters from South American countries made their way to the US over several more years, adding much needed new genetics into the captive anteater population. Today, Nashville Zoo is home to the largest collection of captive giant anteaters in the United States.
Fecal hormone metabolites profile in an adult female. (A) Profile of fecal P4, E1, and E2 metabolites over a 20 month period in an adult female giant anteater (Monita, SB314) after two consecutive pregnancies (prior parturition date of 1/25/03). (B) Profile of fecal GC metabolites in the same female giant anteater during estrous cycling.
Fecal hormone metabolites during the estrous cycle of female giant anteaters. Mean weekly concentrations of fecal P4 and E1 metabolites during the estrous cycles: (A) a multiparous female (Monita: n = 6 cycles), and (B) two nulliparous females (Emelia and Lia: n = 6 cycles). Data are reported as mean SEM each week relative to the peak E1 concentration during estrus. Note the shorter estrous cycle length (B, mean, 47 days) and the three-fold lower concentrations of P4 metabolites in the nulliparous females relative to the multiparous female (A, mean estrous cycle length, 62 days).
Fecal estrogen and glucocorticoid metabolites during pregnancy. Profile of (A) E1 metabolites, (B) E2 metabolites, and (C) GC metabolites in the feces of three female giant anteaters during pregnancy. Concentrations are reported as the average SEM during each week of the pregnancy.
Although hormone concentrations and lengths of estrous cycles for giant anteaters reported in this study were similar to previous reports of xenarthrans ([10]; Table 3), we also report here that estrous cycle lengths of younger nulliparous females were 14 days shorter and P4 metabolite concentrations over 2-fold lower than those of a multiparous female. In this study, the multiparous female exhibited the anticipated polyestrous profile of giant anteaters as exhibited by regularly spaced E peaks occurring throughout the year. Each E peak was followed by an elevated concentration of P4 confirming ovulation and formation of functional corpus lutea. In contrast, younger nulliparous females had more intermittent and shorter estrous cycles or endocrine profiles that exhibited unclear ovarian activity (e.g., luteal activity without an observed estrogen peak or parallel steroid hormone profiles). All females were housed with a male for the duration of the study except when parturition was expected, and keepers also shifted males to find optimal pairings. At the Nashville Zoo, managers reported that after females were paired successfully with a male (i.e., living with each other without confrontation) they become quite bonded and would sleep together in the same kennels (P. Riger, personal communication). This bond may have been stronger for the multiparous female as she was older, had been at the facility for a longer period of time, and thus more accustomed to the presence of males. Although copulation was not observed, it is still unknown whether olfactory, tactile, or visual cues brought about by the presence of the male are required for ovulation in giant anteaters. Thus, irregular holding or shifting of males could explain the variable estrous cycle patterns and longer return to estrus post-partum in some females. Seasonality of breeding in wild populations is an evolutionary process where individual species react to weather, food security, habitat changes, and the availability of mates. In a zoological setting, food, habitat and general safety variables are taken away and animals are held in an optimal setting all year long excluding the need for seasonal breeding (and parturition date). Variation in the ovarian activity of nulliparous females in this study may also have been a result of their relatively younger age. Age at first reproduction for the majority of captive giant anteaters ranges 2-4 years [3,4,26], although a single female giant anteater was reported to give birth at 1.6 years [1,2]. The youngest pregnant female in this study was 1.8 years of age and this female did not exhibit clear ovarian cycling prior to breeding. Two other females in this study (Maripi and Gabriella) were similar or older in age (
Validation of enzyme-immunoassays. Parallelism between standards and extracts of giant anteater feces for (A) progestagens, P4, (B) estrone-3-glucuronide, E1, (C) estradiol-17β, E2 and (D) glucocorticoid, GC, metabolites as determined by enzyme immunoassay (see Methods).
The Potawatomi Zoo is a sponsor of the conservation project Anteaters & Highways (www.giantanteater.org) in support of research to address the threats to Giant Anteaters and help save this iconic species in the wild. 2ff7e9595c
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