Edinburgh Zoo’s larger than life Sclater's lemurs are on a diet. Since November keepers have been changing their diet to encourage weight loss, and in recent weeks have been trying out experimental new feeders that make the animals work for their food but also allow the lemurs to feed on smaller quantities over a 24-hour period.
Initial results from the diet changes have been positive and reports from the researchers who placed the feeders in the enclosures for four weeks, suggest that the lemurs spent an increased amount of time moving about as they were unsure when or which feeder would be the source of the next meal. Zoo keepers are now considering if the feeders should be put in the enclosure over a longer period to help shift the lemurs’ lingering last few pounds.
As Lorna Hughes, Head Keeper for Primates at Edinburgh Zoo said, “In the wild, lemurs feed on seasonally available wild fruit which is naturally lower in energy than cultivated fruit which is often fed to them by zoos all year round. So we have now introduced a new diet that focuses on low calorie healthy alternatives and have moved from a fruit to a more vegetable-based menu. The results have been really positive but we decided we needed to look at additional options to maximise the animals’ weight loss.
“The second phase of the programme was designed to complement the diet changes by providing ways to stimulate the animals and encourage greater activity levels. Just as with humans on a diet, watching what you eat combined with increased exercise will result in a higher weight loss. In the wild, lemurs have a 24-hour activity cycle and would eat little and often so by using the feeders we also were able to try this out by giving five smaller feeds instead of three larger ones over a 24-hour period.”
Working with Brendan Duggan, a trainee researcher studying the MSc in Applied Animal Behaviour and Animal Welfare at Edinburgh University, purpose-built automated feeders were introduced to the lemurs’ enclosure at the end of June and were placed in high locations.
As Brendan said, “In the wild lemurs will spend 32% of their day foraging and feeding as opposed to 14%[i] in captivity, so it was important that we made these otherwise laid-back lemurs work for their food. Our results showed that once the feeders were introduced the time these lemurs spent resting decreased. The unpredictable nature of the feeding regimes meant that instead of waiting for the sound of dinner approaching with the turn of a keeper’s key, they were constantly checking the feeders never knowing when or where they might find food being dispensed. As the feeders also keep dispensing food, the novelty never seemed to wear off.”
Originally weighing in at 3.58kg, the female (Noemie) has already lost nearly three quarters of a kilo (now 2.87kg) but has another 290grams to go before she reaches her target. The male (Bobby) has struggled as many others do and is still battling the bulge despite now having lost 300g off his pre-diet weight (currently weighing 3.1kg) he still has to reach the target weight of 2.6kg .
With only two zoos in the UK having this species of lemur in their collections (the other being Colchester), Sclater's lemurs (Eulemur macaco flavifrons) also known as blue-eyed black lemurs, are prone to weight problems. Obesity in lemurs has health implications, such as coronary heart disease and diabetes, and is also a major obstacle for breeding. This species is listed as endangered by the IUCN , showing that there is a real threat of extinction in the wild, so captive collections could provide the only insurance policy these little guys have left. And while food may be the language of love for some, for these fellows more weight equals less libido and they are less likely to get up to monkey business!