Reproductive Patterns in Tamandua (Tamandua tetradactyla)

• Published in: Journal of zoo and wildlife medicine 1994-06, Vol.25 (2), p.248-258
• Main Authors: Hay, Margery A., Bellem, Astrid C., Brown, Janine L., Goodrowe, Karen L.
• Format: Article
• Language: English
• Subjects: Cytology; Erythrocytes; Estrogens; Mating behavior; Semen; Spermatozoa; Steroids; Urine; Urine specimen collection; Zoos
• ISSN: 1042-7260; 1937-2825

The tamandua (Tamandua tetradactyla) or lesser anteater is a member of the family Myrmecophagidae in the order Xenarthra (Edentata), which consists of neotropical sloths, anteaters, and armadillos. Little is known about this order in general or tamandua in particular. Because of the difficulty in obtaining field data and the poor propagation record of the few specimens listed in the International Species Inventory System (ISIS), captive xenarthrans are a valuable source of physiological and behavioral information for this order. Daily urine samples were collected from two female tamandua over 420 days and analyzed for concentrations of estrone conjugates (EC), pregnanediol-glucuronide (PdG), and cortisol concomitant with collection of vaginal smears to correlate changes in vaginal epithelial cells with endocrine patterns. Hormonal analyses indicted that one of the females demonstrated regular estrous cycles lasting 42 ± 3 days with no apparent effect of season. Based on the rise and fall of PdG values, the luteal phase lasted 23.4 ± 1.0 days (n = 10) with peak PdG concentrations (18 ± 0.8 ng/mg creatinine [Cr]) occurring 12 days later than peak EC (37 ± 11 ng/mg Cr). Examination of vaginal cytology indicated the occurrence of red blood cells 1-3 days prior to and during the rise in urinary EC; however, stained vaginal epithelial cells displayed no clearly defined pattern of cornification. The second female had regular bloody vaginal discharges that occurred every 40 days and lasted 7-12 days without any corresponding changes in excretory endocrine patterns. Although concentrations of estrogen and progesterone metabolites in the urine were greater during the initial three cycles compared to subsequent cycles, there was no correlation between declining ovarian steroid levels and urinary cortisol concentrations. A better understanding of the reproductive physiology in this particular species could assist in the captive breeding not only of small anteaters but also of the more threatened anteater species.