Rusa deer originate from the islands of Java and Bali in Indonesia. They were introduced to Mauritius by Adrian Van der Stel, a Dutch governor who came to Mauritius in 1639. They have characteristic large ears and round eyes, as well as light tufts of hair above the eyebrows. Rusa males are larger than females, and fully grown can weigh 140 to 160 kilograms, while females’ average weight is 75 kilos. The males have large lyre-shaped three-tined antlers, which they use during mating season to compete with other males. During the rut, they are extremely vocal and decorate their antlers with grasses and twigs to attract females, usually between the months of July and August. After the mating season, they will shed their antlers and grow new ones. These deer live between 15 to 20 years in the wild or in captivity.
The deer prefer open dry and mixed deciduous forests, parklands and savannas. However, they are a flexible species who have been known to adapt to live in forests, mountains, shrublands and marshes; habitats between sea-level and up to 900 meters. Their diet consists primarily of grass and leaves, but their dentition and mouth shape allow them to eat herbs, bark, and even seaweed. Rusa deer are gregarious animals who live in herds of up to 25 individuals, however males and females tend to live separately except during mating season. They are a diurnal species but are known to gather in large groups in open areas during the night and are particularly active at night during the mating season.
The deer is classified as ‘Vulnerable’ in the IUCN Red List of Threatened species due to the declining and low number of individuals present in its native range. The Javan rusa are native to Java and Bali, but has been introduced to Australia, Brazil, Malaysia, Mauritius, New Caledonia, New Zealand, Papua New Guinea, Thailand and Timor-Leste. Most populations occur outside its native range, with fewer than 10,000 mature individuals in contrast to approximately 60,000 found in Mauritius. Habitat loss and degradation and poaching are leading to a continuing decline in the population in its native habitat. The Javanese deer is highly praised for hunting game and the absence of predators in reserves make it unlikely that the herds would be threatened with decline in Mauritius.
Individual animals from the Mauritian herds were re-introduced to Java in 1989.
Le Chasseur Mauricien. 2018. History of the Rusa Deer. https://www.lechasseurmauricien.com/en/history-of-the-rusa-deer.html.
Reyes, E. 2002. "Rusa timorensis" (On-line), Animal Diversity Web. at http://animaldiversity.org/accounts/Rusa_timorensis/