Howler Monkeys in Fragmented Forest “Islands” in Southeastern Petén, Guatemala
One of the joys of camping and conducting archaeological work in the National Park of Ucanal in Petén, Guatemala, is waking up to the sound of black howler monkeys (Alouatta pigra; saraguate) : “OOOHHHHH, AHHHHHH, OHHHHHHHHHHHH, AHHHHHH”. They accompany us along the treetops as we walk through the forest, and they intently observe us from above while we excavate and map the ancient Maya city of Ucanal, known in Classic period times as K’anwitznal. Although we have not conducted a demographic study of their population numbers, their consistent proximity to camp and their repeated and frequent presence at multiple research locations throughout the park, as family groups or individually, suggest their population density is high.
Despite our delight in living among such vocal and friendly non-human relatives, we note several concerns for the well-being of howler monkey communities in the park and elsewhere in Southeastern Petén. Firstly, their habitat is part of a fragmented forest environment. The national park that protects a small portion of the ancient city of Ucanal is small at 1.4 km2. Although other forest patches of a few square kilometers in size are scattered nearby, many of these forest fragments have shrunk considerably over the last 20 years, creating “islands” on which howler monkeys and other high canopy forest species become trapped. Forest fragmentation has the potential to pose problems with in-breeding over the long-term as well as the catastrophic loss of biodiversity, both flora and fauna.
Secondly, our archaeological project’s mapping team in June 2023 identified a high number of howler monkeys that had recently died. Over the course of 4 weeks, 6 recently deceased (found as partially or completely articulated remains, some still with soft tissues) howler monkeys were found by our team in a <0.4 km2 zone of the park. Antidotally, this has lead the team to label one of the ancient residences, 576 Baatz’, meaning howler monkey in various Maya languages. Until further studies are conducted, we cannot pinpoint the cause(s) of death (e.g. diseases shared by human and non-human primates, poor quality water). Nonetheless, the park’s guards noted some changes in their voices (one with an unusual raspy voice) and behavior, such as their descent to the ground to drink water from the Río Mopan. To date, 2023 was the hottest year on record and as such, howler monkeys may be increasingly forced to obtain other sources of water than fruit and leaves and thus exposed to poor quality river water. Howler monkeys, like other non-human primates, are indicator species that reflect the health of their habitat.
Google Earth Map showing the forest fragment of the Ucanal National Park, Petén, Guatemala (red line), location of 2023 howler monkey skeletons, and mapped ancient architecture (white).
Thirdly, howler monkeys are increasingly at risk throughout Central America. Although howler monkeys are highly resilient primates,1 the human-caused deforestation of Southeastern Petén is unprecedented in human history. There is increasing reliance on cattle ranching and logging that began to pick up after the 1960s and has been increasingly exacerbated in the last 20 years.2 A 2020 assessment of the IUCN Red List of Threatened Species has listed Alouatta pigra as ‘Endangered’ under criteria A4cd.3 The Classic period Maya (ca. 300-800 CE) considered howler monkeys as wise practitioners of scribal and pictorial arts.4 Let’s call forth humans to be equally wise and consider new forest management strategies.
Christina Halperin, Université de Montréal
Carolyn Freiwald, University of Mississippi
Hugo Roberto Lara Figueroa, Universidad de San Carlos de Guatemala
Jean-Baptiste LeMoine, Université de Montréal
1 Bolt, Laura M., Colin M. Hadley, and Amy L. Schreier. 2022 Crowded in a Fragment: High Population Density of Mantled Howler Monkeys (Alouatta palliata) in an Anthropogenically disturbed Costa Rican Rainforest. Primate Conservation 36:1–9.
2 Devine, Jennifer A., David Wrathall, Nate Currit, Beth Tellman, and Yunuen Reygadas Langarica. 2020. Narco-Cattle Ranching in Political Forests. Antipode 52(4):1018–1038. DOI:10.1111/anti.12469.
Schwartz, Norman B. 1995 Reprivatización y privación: sistemas tradicional y contemporáneo de tenencia de la tierra en el Petén, Guatemala. Mesoamérica 29 (junio):215–232.
3 Cortes-Ortíz, L., Rosales-Meda, M., Marsh, L.K. & Mittermeier, R.A. 2020. Alouatta pigra. The IUCN Red List of Threatened Species 2020: e.T914A17926000. dx.doi.org/10.2305/IUCN.UK.2020-3.RLTS.T914A17926000.en. Accessed on 13 December 2023.
4 Rice, Prudence M., and Katherine E. South. 2015. Revisting Monkeys on Pots: A Contextual Consideration of Primate Imagery on Classic Lowland Maya Pottery. Ancient Mesoamerica 26(2):275–294. DOI:10.1017/S0956536115000206