In recent days, the Internet of Things (IoT) used to connect many devices and communicate with each other, which created a greater impact on animal healthcare systems. IoT devices are in the form of wearable’s that have been used to track the activities of humans. Now, the wearable devices are used in monitoring the activities of the animals. Internet of Things in Animal Healthcare (IoTAH) uses the biosensors and software for monitoring and maintaining the animal health records. These kinds of technologies make a precise health status and sickness projection which are most effective in humans but it can be applied to animals with few changes. Some of those recent technologies acquired the importance of their use in animal healthcare and development. The integration of available medical sensors creates a connected digital platform that empowers the connectivity with pets and livestock with improved efficiency. This article describes the scope of biosensors, computing, communicating, and wearable technologies available for animals. The main intention of this article is to review the recent advancements in the field of animal healthcare which includes domestic, farm, and wild animals. This article reviews the smart technologies available for various categories of animals. The outcomes of this survey are expected to improve the future research and development of animal welfare systems.