GROWTH PATTERN DIFFERENCES OF CAPTIVE BORN ANTILLEAN MANATEE (TRICHECHUS MANATUS) CALVES AND THOSE RESCUED IN THE BRAZILIAN NORTHEASTERN COAST

Abstract

The aim of this work was to analyze whether there are differences between the development pattern of Antillean manatee (Trichechus manatus) calves born in captivity and those rescued and kept under rehabilitation. Biometrics data were collected from 1990 to 2010 from 38 calves, 29 of which still had the remnants of the umbilical cord and had been rescued from the Brazilian northeastern coastline (Group I), and nine individuals that were born in captivity and remained with their mothers (Group II). Among the measures obtained through biometry, the total length and weight of the animal were recorded. Given that the breastfeeding of calves occurs approximately until the age of 2 yr, data obtained until the 24th month of life of each individual were evaluated. An average increase in weight of 53.50 +/- 38.54 kg (mean +/- standard deviation [SD]) was detected in Group I and a gain of 106.87 +/- 47.21 kg (mean +/- SD) in Group II. From months 13 to 24, no significant difference in the weight increment was observed. A similar pattern occurred with regard to the increase in the overall length during the first year, where animals from Group I grew 34.81 +/- 17.94 cm (mean +/- SD) and from Group II grew 83.83 +/- 28.21 cm, a statistically significant difference. The growth was not significantly different from 13 to 24 mo. The results found in this study identified the need for a review of the nutritional diet offered to orphaned calves rescued and kept in captivity. The results also support the need for a better adequacy of facilities for these animals as a way to encourage the management strategies adopted for manatee calves maintained in captivity.

Three Decades of Antillean Manatee (Trichechus manatus manatus) Stranding Along the Brazilian Coast

“…Specimens rescued alive (n ¼ 77) were significantly smaller than those found dead (Mann-Whitney ¼ 503, df ¼ 1, p < .001; Table 1; Figure 4). Only two manatees rescued alive were not newborns according to the classification of Borges et al (2012), their sizes being consistent with those of specimens older than 2 years old.…”

Spatiotemporal dynamics of mangrove forest and association with strandings of Antillean manatee (Trichechus manatus) calves in Paraíba, Brazil

“…The timeframe was 1980–2019. In the present study, only manatees characterized as calves were considered, with average length of 123 cm and 34 kg of weight for newborn (Borges et al ., 2012). Information was compiled on the date, location and geographic coordinates of each stranded manatee calf.…”

Manatee calf call contour and acoustic structure varies by species and body size

“…The body length of the Amazonian manatee remains relatively stable through the first year and increases slowly thereafter 46 , 48 . In contrast, the West Indian manatee species grows exponentially faster over the first year 37 , 49 . Body length may also partially explain the differences in duration of calls between species, i.e., Amazonian manatee calves produced shorter duration calls.…”

“…Manatees tend to grow rapidly from birth. In the first year of life, captive Antillean manatee calves gained an average of 106 kg and grew an average of 83 cm 37 . Research on Amazonian and Antillean manatees suggests that the fundamental frequency becomes more defined as the calf grows to a more adult-type call 17 , 18 .…”