Jane Goodall's cause of death has been revealed. According to her death certificate, obtained by TMZ on Monday, the conservationist died from cardiac arrest, also known as cardiopulmonary arrest. The risk of cardiac arrest rises as a person ages, and so with that in mind, the death was considered natural. After all, the beloved primate expert was 91 years old. Related: Did Liam Payne's Sister Ruth Just Shade His Girlfriend?? Jane also had epilepsy, as listed on the certificate, but it is unclear if that played any factor into her death.