During our visits to Gambian forests, we’ve always paid special attention to TRC, knowing them to be Critically Endangered (CR) and their global distribution to be very limited (making The Gambia critical for their survival). Many of our student projects have focussed on what types of plants they eat (especially at the end of the dry season when food is scarce), and others have looked at their movements and behaviour. TRCs are folivores, i.e., they mostly feed on leaves and flowers, and it has always been thought that their diet provided all the water they need, as drinking had only rarely been observed. Dawn Starin had previously observed nursing mothers licking moisture off leaves etc. but drinking from pools had never been observed.

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On two of our dry season university field courses, we had observed the sad scene of mother TRCs carrying dead babies around with them for several days. We tried to follow them to retrieve the dead babies to allow post-mortem inspection for signs of diseases etc. but the mothers kept carrying them until after field courses had left. During visits in the dry season the following year, we were happy to see that no mothers were carrying dead babies. Following a discussion with colobus expert Alison Hillyer after fieldwork one day, a possible explanation began to emerge. She was excited to announce that she had just seen TRC drinking from pools in Abuko forest, and we told her we had just seen the same in Bijilo Forest. Sorting through the hundreds of trail cam images from Bijilo that we had collected that year, it became clear that female TRCs, especially nursing mothers, were regularly drinking from the newly-created waterholes (built by the park staff with financial support from the Tour Guides Association and Project Wild Gambia). The image below shows the nursing mothers drinking (you can see a baby's hand clinging to its mother on the female on the right).