By Olivia Crowe @oliviakcrowe
Crouching at the base of a tree, breathing slowly to keep my binocular-clad hands steady. I watch as all but one flurry of grey scatters out of sight. Tiny, the two-month old infant is still clinging to the underside of a low branch on the large feeding-tree. As hot beads of sweat drip into my eyes and unable to intervene, I see the pale-face of the little monkey, frozen, hoping one of his family members will clamber down to his rescue.
Deep in the Yasuní Biosphere Reserve in Ecuador, the pygmy marmosets had been feeding on tree sap from the holes they had gouged out of tree bark. Their specialised teeth make this their core food source, determining their family life around a central trunk and the vines laced above. This sweet sap attracts many unwanted visitors, as it is a rich resource of energy-giving sugars. During the dry season, tamarins – larger, cat-faced monkeys – will swing down and steal the supply, sending the marmosets into hiding. Little was known about this relationship, leading me to spend a number of months describing their interactions and discovering the challenges they face under primatologist, Dr. Stella de la Torre.
As the smallest monkeys in the world, pygmy marmosets have many names: finger monkey, mono de bolsillo (pocket monkey), and my favourite; leoncillo meaning ‘little lion’. Despite this fierce label, the marmosets avoid confrontation, instead remaining vigilant to the forest sounds with quick reactions. Their timid nature is justified by their small size, which makes them particularly vulnerable to predators (like snakes and birds) as well as habitat disturbances. However, it’s not just the cycles of the jungle that pose a risk to their survival.
In 2008, researchers called for pygmy marmosets to be listed as Vulnerable by the IUCN. In northern Ecuador, three scientists found that 75 – 85% of their forest-edge habitats were affected by logging and agriculture. Despite their wide distribution, pygmy marmoset expert Dr. de la Torre lamented that “over the past 10 years, the populations seem to be contracting”, as marmosets regularly vanish from her study sites. Although their total population size was unknown and declining, it was not enough to change the status of the monkey. More recent discoveries may change that fact.
Pygmy marmosets inhabit the forests of five countries but in late 2017, evolutionary biologists redefined this distribution. By examining DNA sequences (from monkey poop!) genomic studies revealed that the pygmy marmoset is not one but two species. These populations have been living separately for almost 3 million years. This surprising division could have big implications for conservation, as each species must be managed separately.
(Map source: Dailymail.co.uk).
Human threats to pygmy marmosets include deforestation and intrusions like disease. As roads and reserves lead humans and their pets closer to monkey populations, alien diseases are introduced, resulting in the death of infected monkeys – known as ‘pathogen pollution’. Marmoset epidemics have already happened in Brazil, spurring the IUCN Primate Specialist Group to recommend that marmosets are given a Vulnerable status. The other major human impact is poaching.
I moved to a finca (small farm) to observe a large, family group living near a rivereño (riverside) community. When I arrived, the group was nowhere to be found. After speaking to local resident, Bertha, I was told that children had captured the juveniles as pets, causing the remaining monkeys to flee.
Marmosets are incredibly social creatures, and can be seen grooming each other, huddling on branches and playing chase – they are also undeniably cute. Their teddy-bear looks have led to their capture by local communities becoming commonplace. Tight family-ties mean that separation has considerable impacts on the marmoset’s health. Adding to this, there is international demand for them as pets –where they are marketed as pocket fashion accessories. Social media has helped to fuel this craze, as cute videos normalise the keeping of wild animals as pets. This activity is most notable in China with juveniles being sold for £3,200 each.
Managing poaching at these levels requires multiple approaches. Close to the marmoset’s home, outreach programmes educate children on the dangers of taking marmosets as pets. In many countries, it is now illegal to import or export them, and they are listed in Appendix II of CITES, which means their trade is monitored and controlled internationally. Despite these crackdowns, they are still bought as pets worldwide and educational websites can be found describing the best way to keep them. This content may aid their captive survival but it also wrongly promotes keeping such monkeys as pets.
Despite their plights, the uplisting of pygmy marmosets to Vulnerable by the IUCN may help to protect them from people and deforestation – and I know, it’s impossible not to fall for them! But the best way you can love these little lions is through a binocular lens.
Special thanks to Dr. Stella de la Torre for introducing me to the pygmy marmosets and taking me under her wing.