Search

We studied development of wings of Leschenault's rousette, Rousettus leschenaulti. Wingspan and wing area grows linearly until 45 days of age. Young bats begin to flutter at 45 days, manage sustained flight at 60 days, and achieve independent foraging flight at 75 days. Aspect ratio varies until 15 days, and adult proportions are attained at 2 months. Wing loading decreases linearly until 50 days and thereafter increases slowly, possibly because of completion of growth of wing area. Wingspan growth fits a logistic model, whereas wing area growth fits a Gompertz model. Minimum predicted flight power (Pmp) and maximum range power (Pmr) begin to increase linearly after remaining relatively constant for 30 days. At 150 days both are nearly equal to 65% of the power requirements of postpartum females. The predicted minimum power speed (Vmp), maximum range speed (Vmr), and minimum theoretical radius of a banked turn (rmin)) decrease for 40 days, thereafter increase linearly, and at 150 days all are close to 90% of the respective values of the postpartum females. [ABSTRACT FROM AUTHOR]

Understanding variability in growth patterns of marine mammals provides insights into the health of individuals and status of populations. Body growth of gray whales ( Eschrichtius robustus ) has been described for particular life stages, but has not been quantified across all ages. We derived a comprehensive growth equation for gray whales by fitting a two-phased growth model to age-specific length data of eastern North Pacific gray whales that were captured, stranded, or harvested between 1926 and 1997. To predict mass-at-age, we used the allometric relationship between mass and length. We found that on average (± SD ), calves were 4.6 ± 0.043 m and 972 ± 26 kg at birth, and reached 8.5 ± 0.095 m and 6,019 ± 196 kg by the end of their first year of life ( n = 118). Thus, calves almost double (2×) in length and octuple (8×) in mass while nursing, and are effectively about two-thirds of their asymptotic adult length and one-third of their maximum mass when weaned. The large sample of aged individuals ( n = 730) indicates that gray whales live up to ~48 years and have a life expectancy of < 30 years. Adult females attain a mean (± SD ) asymptotic size of 13.1 ± 0.048 m and 20,758 ± 222 kg, while the smaller males average 12.6 ± 0.048 m and 19,938 ± 222 kg at ~40 years of age. Females are thereby ~4% longer and heavier than males. These age-specific estimates of body size can be used to estimate food requirements and assess nutritional status of individuals., (© The Author(s) 2020. Published by Oxford University Press on behalf of the American Society of Mammalogists.)