Michelle G. Barrows

Interest in the welfare of zoo animals is strong, both within the professional zoo community and among the general public. Maintaining the highest standards of animal welfare is a key priority for keepers, curators and zoo veterinarians, and zoo animal welfare science has advanced considerably in recent years.

Dermal melanocytic neoplasms are common in some even-toed ungulates (Artiodactyla), yet this entity has not been reported in the pygmy hippopotamus to date. Concurrent occurrence of multiple benign and malignant melanocytic neoplasms is unusual. Malignant transformation occurs in a small percentage of benign melanocytic tumours in people but this phenomenon has not been well documented in animals.