The design and test is described of a small size dual band implantable antenna operating in Medical Implant Communications Service (MICS) (402 MHz-405 MHz) and Industrial, Scientific and Medical (ISM) (2.4 GHz-2.48 GHz) bands to be used in animal studies for medical research. The antenna is intended for wireless medical monitoring of the physiological parameters such as glucose, pressure, temperature, etc. First, the electrical properties (epsivr and sigma) of skin samples from donor rats are measured at Mississippi State University's (MSU) College of Veterinary Medicine. A dual band antenna is then designed using an in-house finite element boundary integral solver in conjunction with particle swarm optimization algorithm. Finally, the antenna is tested using both skin-mimicking materials and real skin samples. The development details of the skin-mimicking materials are also given. Results regarding the S11 and gain of the designed antenna are given and discussed in detail.