Breakthrough: High rates of infant mortality caused by maternal energy depletion from lactation in harsh environments.

Dittus, WPJ and Baker, A. (2023). Maternal care in wild toque macaques involves prolonged lactation & IBIs as adaptations to reduce maternal depletion & infant mortality in harsh environments. American Journal of Primatology, e23584. DOI: 10.1002/ajp.23584
Abstract
Weaning age in primates has been challenging to measure and new methods, involving molecular biomarkers in feces, tissue, or teeth have contributed to a solution. Here, we used a direct approach by briefly anesthetizing 442 female toque macaques (Macaca sinica) of Sri Lanka (over a 17‐year period) and manually testing their mammary tissue for the presence or absence of milk. Milk tests were related to known offspring ages and maternal care behaviors and indicated that older infants suckled milk well past the weaning age of 7 months that is often reported for food provisioned primates. Mothers strongly rejected their infants’ nursing attempts in two phases, the first at 7 months as an honest signal “giving notice” promoting a shift to greater independence from milk to solid food, and when “shutting down” at final weaning after 12–18 months. The shift to supplementary lactation coincided also with the cessation of mothers carrying their infants and a resumption of cycling. All infants up to 7.2 months suckled milk, 91% of them did up to 18 months, this continued for 42% of infants beyond 18 months, and normally none received milk after 22 months. Lactation extended into 2.2% of cycling and 10.7% of pregnant females (up to 50% of gestation). The interbirth interval was prolonged by factors predicted to draw on female metabolic energy reserves and included the duration of lactation, growth among primiparas, and dietary limitations. The last also increased menarche. Females offset the metabolic costs of lactation with increased foraging […]

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“Our” researched monkeys filmed in 4 NEW documentaries, 2019

 

Preview: A Life Among Monkeys, Smithsonian Channel (USA) (23rd April broadcast). The film documents the 50 years scientific career of Professor Wolfgang Dittus and his cutting edge discoveries about primate social behavior.  Introduction by Dr. Jane Goodall.  .

First Year in the Life of a Toque Macaque. BBC Natural World.  Follows the life of a toque macaque baby named Jazeer, son of alpha female Jemuza, and the trials of tribulation of growing up in a competitive society of toque macaques where it helps in mom is the queen.  

Preview: Monkey Island. Animal Planet.  A cross-section in the daily social life of toque macaques, their dynasty and its challenges in the forest of among the ancient ruins of Hindu and Buddhist temples of a bygone civilization. . Preview.

Ein Leben unter den Affen. Alma Mater    Narrated in German, the film documents the 50 years scientific career of Professor Wolfgang Dittus and his cutting edge discoveries about primate social behavior.  Introduction by Dr. Jane Goodall. .

 

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Editor’s choice: Reducing human-monkey conflict

Assessing public perceptions and solutions to human-monkey conflict from 50 years in Sri Lanka

Authors: Dittus, Wolfgang PJ;  Gunathilake,  KA Sunil; Felder, Melissa

Folia Primatologica 90: 89-108. (2019)   DOI: 10.1159/00049602.   Research Article

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Abstract.  Sri Lanka is a biodiversity hotspot with high human density that contributes to increasing human-monkey conflict (HMC). In 50 years of primate studies there, the development of HMC has been documented, and many workshops and interventions organized to ameliorate HMC. These activities prompted the present survey. In the extensive lowland dry zone of Sri Lanka, the affected nonhuman primates are the toque macaque, gray and purple-faced langurs and slender loris. We surveyed and evaluated the attitudes of rural residents towards these four species in an effort to contribute to an ethnoprimatological approach to conservation, i.e., promote a coexistence and sharing of habitat between humans and monkeys. We selected 13 villages near Polonnaruwa, located centrally in the dry zone. The four nonhuman primate species differ in their behavioral ecologies, and this influenced how frequently they were thought of as pests. Most HMC was with the macaque and gray langur, less with the purple-faced langur and least with the loris. The underlying sentiment among stakeholders towards monkeys was generally either neutral or positive. Nonetheless, the majority (80%) of persons desired a translocation of the troublesome monkeys from their properties to protected areas, which is impractical. Few (<1%) openly wanted monkeys destroyed. While a traditional reverence for monkeys provides a solid basis for science and media-based education, it also contributes to the feeding of monkeys and consequent unnatural population growth, and enhanced HMC. Public understanding of the underlying causes of HMC was poor, hindering effective solutions. A combination of a feeding ban, possibly contraceptive intervention […]

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Most popular with 25,000 reads: Fantastic history of Sri Lanka’s mammals

The biogeography & ecology of Sri Lankan mammals point to conservation priorities

 

Ceylon Journal of Science 46 (Special Issue): 33-64. (2017)    Research Article

Author:  Dittus, Wolfgang PJ

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Abstract: All mammals originated on the supercontinent of Pangaea in the Mesozoic era during the “Age of Reptiles.” However, the crown ancestors of contemporary mammals did not flourish until major environmental and biotic changes had occurred. An asteroid collided with earth at the end of the Cretaceous Period (the K-Pg boundary event) wiping out non-flying dinosaurs and primitive mammals. It was followed by large-scale volcanism, a spike in atmospheric oxygen and the proliferation of flowering plants. New niches became available for the ancestors of today’s mammals to fill. Evidence suggesting whether the ancestors of the Sri Lankan and Indian mammals originated on the tectonically marooned Indian plate before crashing into Asia or on the Laurasian supercontinent is inconclusive. Modern Sri Lankan mammals show their greatest affinity with those of southern India, and were more diverse in the Pleistocene when rhinoceros, hippopotamus, wild dogs, gaur and lions enriched the island’s landscapes. Native Sri Lankan land-based mammals are diversified into about 108 unique taxa (among 91 species and 53 genera), differentiated as phenotypic adaptations to sharply contrasting environments among seven major phyto-climatic zones. Endemic subspecies are distributed fairly equally across different phyto-climatic zones (n=24 to 29), except in the highlands where they are fewer (n=14) having evolved rapidly to species and genera among the insectivores and rodents whose reproductive rates are high. Conversely, greater numbers of endemic species (n=13) and genera (n=3) occur in the highlands than in the other zones (2-6 endemic species, no endemic genera). The prevalence of endemism is inversely related to body size […]

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Monkey Kingdom: Sri Lankans star in Hollywood epic

April 2015. After 3 years of filming our research subjects, the toque macaques, at our study site at Polonnaruwa, DisneyNature premiers the film in Colombo in August.

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Incultrating professionalism for national development

August 2015. Dr. Dittus chairs the plenary session on Pragmatic Research for Devleopment and Prosperity at the 8th International Research Conference at the General Sir John Kotalawala Defense University

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The importance of acknowledging the diversity of mammal subspecies

Jan 2014: Ceylon Journal of Science (Bio). Subspecies of mammals are critical to estimates of Sri Lankan biodiversity, set Sri Lanka apart from the Western Ghats as a global biodiversity hotspot and invites revision of current harmful conservation management practices.

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A pinch of skin to estimate body fat in monkeys

April 2015. The precision in growth and allometric development makes it possible to accurately estimate the mass of body fat in different regions of the body given the known relationship between skinfold thickness and mass of dissected adipose tissue.

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Macaque seeks refuge in U. S. embassy

January 2013. Conflicting press reports about macaque breaching  embassy security
A macaque had found its way into the U. S. embassy compound in Colombo on 20 December, 2012, and caught the attention of the leading newspaper in the American capital, the Washington Post, which ran three different articles on the event.  Sri Lankan newspapers, The Sunday Times and The Island, too, picked up the story.  All papers agree that a macaque monkey was found inside the embassy compound without triggering any security alarms.  Embassy staffers secured their offices from the intruder and alerted their own marine guards as well as the Department of Wildlife Conservation (DWC).  According to the Post, the U. S. marines chased the monkey into the adjoining compound – the British High Commission, but the Sri Lankan papers credited the DWC with restraining the panicked marines, capturing the tranquilized monkey and setting it free in the wild.
While newspaper reports appear to be serving different political needs, I herewith offer my own point of view.  Despite the fact that toque macaques are an endemic species, the Sri Lankan government had recently declared the species as a pest and, at the cost of millions of rupees, had distributed guns to the public to shoot macaques (a fact). Toque macaques are being persecuted in a most shoddy manner in this Buddhist country!  I suggest that this intrusive monkey most likely was an escaped or evicted pet from a Colombo residence where it had learned about its intended genocidal fate and sought asylum in the U. S. embassy.  Having been denied refuge by the Americans, it tried its luck with the Brits.
Wolfgang Dittus, PhD
Primatologist

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Nature Education for Teachers

28 August 2012. ACPD staff instruct teachers on nature and conservation
Staff of the Smithsonian Primate Research Station conducted a wildlife conservation and nature education program for 25 school teachers from the Polonnaruwa education zone. Provincial Director for science education,  Mr.SM Saluwadane, Zonal Director for science education,and Master in charge of the nature center at the Royal college Polonnaruwa participated for the program.  This session represented an expansion of ACPD staff teaching of students, to include a new phase involving teacher training in the Polonnaruwa District.

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