Other Species: Seals, Elephants, Macaques


Although grey seals (Halichoerus grypus) were hunted earlier, pup production on Sable Island in Nova Scotia has been increasing exponentially at an annual rate of 12.8% for the past four decades (Bowen et al., 2003, Journal Marine Science 60(6): 1265–1274). SpayVac immunocontraception offers a humane alternative to culling to control these populations. One-hundred one (n=101) wild female grey seals were treated with a single injection of SpayVac, and fertility rates dropped from an average of 70% for controls to 12% for treated animals for 10+ years with a single-dose. See Brown et al. 1997 for details about the initial 5-year study


As free-ranging populations of African (Loxodonta africana) and Asian elephants (Elephas maximus) become increasingly confined to smaller ranges, concerns grow about human–elephant conflicts and negative impacts on flora and fauna.  A group of 6 captive African elephants were vaccinated with a single injection of SpayVac, and pZP antibody titers were first detected 4 weeks post-vaccination but did not peak until 1 year, after which they remained consistently elevated through 7+ years.  Additional research is needed to determine actual contraceptive efficacy in these animals and how SpayVac could work in Asian elephants.  See Bechert and Fraker, 2016 for details about this promising initial trial.


One trial was completed with Macaques in Hong Kong previously and another trial with Macaques and SpayVac was initiated in 2020. We expect to have more information to share once there is data from this second trial.