MEDICAL MANAGEMENT OF DILATED CARDIOMYOPATHY IN LIVINGSTONE FRUIT BATS ( PTEROPUS LIVINGSTONII )

Weight as an indicator of enclosure suitability in Livingstone's fruit bats (Pteropus livingstonii)

Obesity is common in zoo animals, and both dietary management and the provision of adequate opportunities for exercise are needed to tackle it. We used 30 years of records from Jersey Zoo to compare the weight and forearm length of wild and captive-born Livingstone's fruit bats (Pteropus livingstonii), and to assess the impact on weight of enclosure space. The mean capture weight of wild-caught male Livingstone's bats was 657 g, significantly higher than that of females (544 g). In both wild and captive-born bats, males had significantly longer forearms than females, but there was no effect of birth location. Males weighed more in the mating season than at other times of year. Both sexes gained more weight during development if born in enclosures that restricted flight rather than a large aviary; this was particularly noticeable in females. After reaching maturity at 3 years, weights of bats born in restricted enclosures continued to increase, reached a peak of over 1000 g at 8-10 years, and then declined in both sexes. The weight of bats born in the aviary remained more stable after the age of three. Like wild bats, adult females born in the aviary weighed less than males. However, females born in restricted enclosures weighed more than males born in the same enclosures. Enclosure designs that maximize opportunities for flight can limit excessive weight gain in captive fruit bats and may therefore improve fitness and health, essential in planning for future reintroduction programs.

Radiographic anatomy of the heart of fruit bats

As the only mammal that can fly, bats have organ systems with a unique morphophysiology. One of the highlights is the heart and blood circulation system, which must be able to meet the needs of blood and oxygen supply when flying. This study examined the radiography of the normal condition of the heart organ in 3 species of fruit bats, namely Cynopterus titthaecheilus, Cynopterus brachyotis and Rousettus leschenaultii using radiological silhouette analysis and clock analogy. The results showed that the heart positions of the three bat species tend to be tilted to the left with the apex moving away from the midsagittal plane. Analysis of intercostal space (ICS) value and vertebral heart score (VHS), and evaluation of radiographic features showed R. leschenaultii has a relatively larger heart size than the other two species. All three bat species have a higher VHS than mammals in general. Radiographic images obtained, and interpretation results show the position, size and normal heart parts of the three bat species. They will be useful in diagnostic efforts related to heart problems in these three species.

Flight patterns in zoo-housed fruit bats (Pteropus spp.)

Maintaining the capacity for sustained flight in captivity is a key goal for the management of threatened fruit bats. We developed quantifiable descriptions of flight complexity and used them to assess the suitability of an enclosure for two species of fruit bat of differing size, the large Livingstone's fruit bat, Pteropus livingstonii, and the smaller Rodrigues fruit bat, Pteropus rodricensis, in a two-part study. In Phase 1, Rodrigues fruit bats flew more often than Livingstone's fruit bats and although the majority of flights in both species were linear, Rodrigues fruit bats were more likely to display complex flight paths involving turns, while flights by Livingstone's fruit bats were more likely to end in a crash-landing than Rodrigues fruit bat flights. The enclosure may therefore not have been large enough for Livingstone's fruit bats to display a full range of flight behavior over longer distances. In Phase 2, juvenile Livingstone's fruit bats ( < 3 years old) flew more than twice as often as younger adults (3-10 years old) did. Older adult Livingstone's fruit bats over the age of 10 years were not observed to fly. We could not separate out the effects of age, weight and environment during development as these factors were strongly correlated in our study; future work in this area will be very important in understanding the factors that affect flight in captive bats, and how it can be encouraged by appropriate enclosure design.