Camera Traps and an Elephant Pregnancy Test
We have set up three camera traps to noninvasively monitor black rhino movements throughout the park, using them to collect fecal samples from known individuals. The camera traps were erected in areas based on rhino sightings by Addo Elephant National Park staff and tourists. We placed them at active scrapings, areas where black rhinos defecate and then scrape the feces with their hind legs to spread odors advertising their presence.
How camera traps work: A high-quality digital photo is quietly taken when the camera (Digital 6.0, CamTrakker) is activated through a passive infrared motion detector. We checked these camera traps early this morning to verify the identity of the individual that defecated and the freshness of the fecal sample from the time recorded on the camera. This morning the camera trap has taken 220 photos...we had not checked it all weekend because we were in Knysa. We have photos of kudu, zebra, lots of elephants, bushbuck, warthogs and an adult male rhino!!
We checked the scraping and found a fresh sample. Because it is in the 30s overnight, the sample has stayed near-frozen; therefore, we can get hormones from the feces. We will be analyzing the sample for testosterone (for reproductive measures) and corticosterone (for stress). It was a successful day for rhino research!
Now onto the elephant project: Dr. Elizabeth Freeman and Jordana Meyer have been investigating the impact of dominance rank on reproductive success in Addo’s elephants. In zoos, many dominant female elephants are not reproductively active (not cycling). Elizabeth and Jordana wanted to determine if this was also occurring in the wild.
They have been collecting fecal samples from female elephants for two years now, which is not an easy task. First, the individuals must be identified. The researchers do this by looking at the elephants’ ear for tears and holes. Then, Jordana sits and waits for the elephant to defecate in an area that is reachable. Not an easy task!! Jordana will then extract the hormones from the feces, and Dr. Freeman has developed a field pregnancy test from a modified enzyme immunoassay for progesterone that works on elephant and black rhinos.