Katherine Christel

Durham & Novy-Hildesley

HUMBIO-18SC-01

14 October 2013

The effect of specialized adaptations of the white-lipped peccaries on their ability to survive the

changing conditions in the Amazonian region.

Abstract

This paper gathers and evaluates population statistics and recent research done on white-

lipped peccary (Tayassu pecari) herds in the Amazonian region of South America. As mammals

exhibiting specialized adaptations fit for an environment that can support large herds, white-

lipped peccaries are currently suffering the effects of extensive hunting and habitat

fragmentation. Through analysis of recent studies and literature based on white-lipped peccaries,

a series of ecological and cultural implications have been drawn about the recent decline in

white-lip populations. Continual destruction of the Amazon Rainforest will only serve to further

the biological and cultural damage done from this upset, and without intervention to protect large

areas of rainforest for the peccaries to thrive on, the rainforest is in danger of losing not only a

component of the Amazon’s biodiversity, but also a key player in the food chain, a prominent

seed disperser, and a significant cultural element to the indigenous groups that inhabit the

Amazonian region.

Introduction to the White-lipped Peccary and its Ecosystem

The white-lipped peccary is a mammalian species inhabiting the Neotropics, spanning

from Southern Mexico to Northern Argentina and from the Andes out to the Atlantic coast.

While they can inhabit dry forests and savannahs, the majority of peccary populations are

concentrated in wet tropical rainforests where they stick close to a water source. As scavengers

feasting mostly on seeds, fruits, nuts, bamboo shoots, and the occasional insects, peccaries tend

to inhabit wet areas dense with fruit and seed-dropping

plants, such as palm swamps (see image 1). When prime

vegetation is not so abundant in the dry season, they will

transition to scavenging in bamboo forests and swiddens.

This diet makes the white-lips key seed dispersers in the

rainforest, and their role in establishing a balance in the

ecosystem does not end there. White-lipped peccaries

have also served as a valuable food source for top

predators such as pumas, jaguars, and boa constrictors, as

well as for indigenous groups, for far longer than western

people even knew of their existence (Csomos 2012).

The physical traits and behaviors exhibited by the white-lips are enough to make them

susceptible to predation. Their large size of 25-40kg, pig-like bodies, bulky heads, sharp canine

teeth, and white markings along the neck in contrast to their coarse, dark fur make them easily

distinguishable from other mammals by sight (see image 2), and the pungent smell given off by

the sweat gland running along their backs is

a give-away from far off. The unique smell

from this sweat gland, combined with their

noisy grunting, barking, and teeth clattering

behavior, allows the peccaries to band

together in large herds ranging from five

Image 1: Palm Swamps

Image 2: White-lipped Peccary Appearance

individuals to well into the hundreds. These traits and behaviors are thought to have come about

as an adaptation to scare away large, aggressive predators with intimidating herd sizes and to

allow for more efficient scavenging for food. The noisy, smelly characteristics of the white-lips

are now suggested to be main contributors to their declining populations as human intervention

changes the status-quo of the Amazon Rainforest (Csomos 2012).

Background on Conservation and Development Dilemmas Involving White-lips

The tendency of the white-lips to utilize their smells and noises as tools of

communication and territorial markings makes their large herds prime targets for extinction due

to logging, habitat fragmentation, epidemics, and illegal hunting. These forces have acted upon

peccary populations to reduce their numbers by approximately 30% over the past three

generations (18 years), and there are no signs indicating a decrease in this rate over the next three

generations. These wide-ranging herds require vast areas of land for survival through foraging

throughout different seasons in the rainforest. With increased hunting pressures by squatters and

poachers, furthered by fragmentation of their habitats creating even more access for hunters to

wipe out entire herds at once, localized extinctions are becoming prevalent in Brazil, French

Guiana, and Bolivia (IUNC 2013). Even regional extinctions have popped up in El Salvador and

Uruguay.

Hunters and poachers are hardly discouraged by the placement of white-lips on Appendix

II of CITIES or the banning of pelt exports in all South and Central American countries other

than Peru while white-lips are selling for $30 for meat and $3 for pelts (IUNC 2013). As of 2005,

historically healthy numbers of peccaries persisted only in 21% of their historic range (Altrichter

et al. 2012). When all of these scary numbers and percentages add up, the white-lipped peccaries

earn a classification as “Vulnerable” overall, but “Endangered” in the Ecuadorian Amazon and

“Critically Endangered” on the Pacific Coast (IUNC 2013). Even the indigenous groups of the

Ese Eja, the Yanomami, and the Wai-wai who have maintained a strong cultural connection with

the white-lipped peccaries and insist that they will always return have begun to notice larger and

larger periods of absence in their presence (Fragoso 2013). All in all, the conservation efforts put

in place by CITIES are proving not to be sufficient in protecting this species as their specialized

adaptations backfire under western human pressures and white-lips become the prey of the 21st

century. As a significant biological contributor to the current balance of the Amazonian

ecosystem and a figure of symbolic importance to the indigenous groups of the area, the white-

lipped peccaries present an alarming case for both biological and cultural preservation.

Hypotheses and Areas of Exploration

The remainder of this paper now shifts to evaluating the effectiveness of the specialized

adaptations of the white-lipped peccaries under the added pressures of habitat fragmentation and

hunting. In order to begin this analysis, we must establish the function that these adaptations

serve the peccaries today. One of these two is an adapted behavior: the loud and aggressive

noises of the peccaries, which have been found to be initiated as warning signs between the

peccaries. The white-lips are known for “whoofing” when first startled, which then gives way to

aggressive “teeth clacking” by snapping their teeth together. They have also been heard barking

and squealing at each other during feeding interactions, which is thought to be a more mild

warning to stick together with the group (Fragoso 1998: 155-156). These noises serve as a form

of communication between the peccaries that allows them to keep large herds in a given range

and protect them from predators. The second of these two adapted behaviors is a dorsal sweat

gland that runs along the spine of the white-lips (see image 3), which gives off a unique smell

depending on which herd a peccary belongs to. This sweat gland functions as a tool for

identifying group members and as a method of marking territory (Csomos 2012). The amount of

sweat and smell secreted increases with the startling of the peccaries (Fragoso 2013).

Living in such large herds is a very “rare

behavior” for large mammals inhabiting the

tropical rainforest, therefore there must have

been some evolutionary advantage to living

in large herds, and therefore to exhibiting

these pungent sweat glands and loud,

aggressive behaviors (Fragoso 1998: 152). This paper will gather results from recent literature on

white-lipped peccaries in order to explore the following hypotheses about the evolutionary

advantage to these adaptations and the current effects of these adaptations on the overall fitness

of white-lipped peccaries:

1. In order to protect themselves from top predators, white-lipped peccaries have evolved

specialized adaptations allowing them to travel in large herds

2. White-lips utilize a pungent sweat gland, noisy grunts, and teeth clattering in order to

foster communication with herds

3. Large herds (see image 4) are now

detrimental to their existence

because constantly shrinking

forested habitats cannot provide

the necessarily large home ranges,

and the noise and smells given off

Image 3: Sweat Gland

Image 4: Peccary Herd

by the peccaries alert hunters of their presence.

Methods

The above hypotheses were tested through recent studies, literature, and interview on the

subject of white-lipped peccary populations. Studies undertaken by various scientists and

ecologists were evaluated for the biological and cultural importance of the white-lips; however,

significant portion of the information gathered in the study of these hypotheses came from Dr.

José M. V. Fragoso, a biology professor from Stanford University who has been researching

white-lipped peccaries since his PhD thesis three decades ago. In 2004, Fragoso published the

results of a multi-year study on white-lips in Northern Amazonia, in which he kept extensive

counts of white-lip populations in various years and radio tracked seven peccaries belonging to

two different herds. His goal in doing so was to evaluate three different hypotheses to explain

white-lip population fluctuations: a.) migration, b.) hunting and poaching, and c.) epidemic

(Fragoso 2004: 287-288). Next, Fragoso’s published work on “Home Range and Movement

Patteerns of White-Lipped Peccary Herds” was evaluated, in which he furthers his descriptions

on this long-term study of Herd A with 39 individuals, which ranged over 22km2, and Herd B

with 130 individuals, which ranged over 109km2 (Fragoso 2006: 458).

Aside from Fragoso’s research, two studies done on the effects of hunting on peccary

populations have provided useful and relevant data for supporting the third hypothesis about the

effects of these specialized adaptations on declines in white-lip populations. In 2000, Laury

Cullen Jr., Richard E. Bodmer, and Claudio V. Pádua published their work the “Effects of

Hunting in Habitat Fragments of the Atlantic Forests, Brazil,” in which they provided a graph

comparing individual sightings of white-lips per 10km of transect to a handful of parks, slightly

hunted sites, and heavily hunted sights. This graph (see figure 1) provides a prime visual

representation of the susceptibility of white-lips to hunting.

Figure 1

In addition to this graph on

hunting and habitat

fragmentation, the effects of

hunting were analyzed in

Carlos A Peres’s study on

the survival advantages of

white-lipped peccaries

versus collared peccaries. In this study, Carlos distinguishes between herd sizes, amounts of

sightings, and extinction potential of the white-lips and collared peccaries (See figure 2). The

compilation of all of these sources provide for the evidence needed to support the three

hypotheses stated above.

Figure 2

Findings

In Fragoso’s published works of 2004, he revealed evidence suggesting a stable home

range and a direct relationship between herd size and extent of home range through radio

tracking, thus refuting the migratory hypothesis. The hunting hypothesis is also refuted as the

only cause of population declines because Fragoso found that populations disappeared even in

areas not penetrated by hunters, poachers, and miners (Fragoso 2004: 292-293). Fragoso

therefore concluded that yet another downfall to large herd sizes are epidemic diseases, which he

later suggested in an interview were most likely brought in from western people through

domesticated animals (Fragoso 2013). He provided evidence that pig and cattle disease outbreaks

in 1989 in Maracá match up perfectly with the disappearance of the peccaries in the Yanomami

area of the island. With herds of over 100 individuals who share overlapping home ranges and

occasionally switch sub-herds, the spread of epidemics brought in by western animals is certainly

capable of decimating large populations of white-lips with no resistance to these exotic diseases

(Fragoso 2004: 294-295).

In “Home Range and Movement Patterns of White-lipped Peccary Herds,” Fragoso once

again highlights the direct relationship between herd size and home range size, but also reveals

his finding through radio tracking that individuals from the herds never venture outside of the

range of the noises and smells of their herds (Fragoso 2006: 465). Radio tracking and extensive

counting of herd members in Fragoso’s long-term study supports the hypotheses that the white-

lips do travel in large herds for protection, and their constant presence within range of the herd’s

smells and noises supports the hypothesis that the adaptations of the sweat gland and the teeth-

clacking are utilized as forms of communication and warning signs between the individuals in

the herd.

The research done by Perez and by the Cullen, bodmer, Pádua team provides evidence in

support of the third hypothesis stating that the specialized adaptations of the white-lipped

peccaries are promoting large, easily locatable herds that are not fit for fragmented habitats and

excessive hunting. As can be seen in Figure 1, white-lipped peccaries are highly susceptible to

hunting and cannot survive on such destructive habitat fragments. Ironically in this chart,

however, the white-lips do survive better in one of the slightly hunted sites than they do in the

park. This can be explained by the lack of agriculture and swiddens grown by indigenous groups

in national parks, therefore limiting the food available to the white-lips living in parks during the

dry season (Cullen, Bodmer, Pádua 2000: 52). Peres’s research supports this graph in showing

that with large herd sizes of 70-260 individuals in the study area, local extinctions of white-lips

are prevalent and especially elevated in heavily hunted territories. This differs from the collared

peccaries studied that lived in groups of 2-8 indiviudals and thrived even in heavily hunted areas

(Peres 1995). In a 2004 study, scientists Keuroghlian, Eaton, and Longland suggest another

potential reason for this alarming difference: large herds of white-lips have a tendency to

confront threats, whereas the first reaction of small herds of collared peccaries is to flee

(Keuroghlian, Eaton, Longland 2004: 422). These sources support the above stated hypothesis

because they provide evidence that hunters are easily locating and decimating white-lip

populations and similarly related species that travel in small herds are able to survive in the same

habitats as the white-lipped peccaries.

Conclusions

The rate of evolutionary adaptation in white-lipped peccaries is too slow when combated

against the rapid changes that humans are causing in the Amazonian region. Western societies

involvement in the Amazon Rainforest has pushed this species to the point where extensively

fragmented areas are no longer recoverable on their own because source populations of white-

lips are no longer available to replace locally extinct populations (IUNC 2013). Without

intervention, the tropical forests risk the chance of losing the last living Neotropical ungulate to

form large herds that forage over vast home ranges, thus altering the entire forest dynamic by

ridding the forest of a key seed predator (Fragoso 1998: 159). As phrased cleverly phrased in a

2009 study on the seed dispersal habits of white lips, “their impacts on soil, litter, and subsequent

seedling dynamics could be considered ecosystem engineering” (Deuroghlian, Eaton, Debiez

2009: 87), and that statement is quite true. Local and regional extinctions of white-lips are

already causing a ripple effect in their previous ecosystems as certain plant seeds are no longer

being dispersed and a food source of another animal is therefore likely to disappear in effect. The

biodiversity loss that would follow the extinction of white-lipped peccaries is frightening.

Even more intimidating is the realization that diversity loss in the case of the white-lipped

peccary also includes huge cultural implications. To indigenous groups such as the Ese Eja, the

Wai Wai, and the Yanomami people of the Amazonian region, white-lips are more than just an

important game animal. They embody a spiritual connection with their ancestors, linked by the

tribe’s shaman. As Dr. José M. V. Fragoso explained in a personal interview, these indigenous

groups see the disappearances of the peccaries as a spiritual sign that a powerful deceased

shaman is unhappy with the tribe. All of the groups tell the same story of how the peccaries will

always return, however, the gaps in between their reemergence keep growing longer and longer.

A scientific approach could show supporting evidence for habitat fragmentation, hunting, and the

influx in exotic diseases causing the population declines, but that evidence means nothing to

indigenous groups who have learned of the spiritual importance of white-lipped peccaries for

centuries upon centuries. In a dissertation project focused on the cultural significance of white-

lipped peccaries to the Ese Eja people, Veronica Ocampo-Raeder writes about the Ese Eja’s

cultivation of bamboo swiddens to lure the white-lips into their hunting and gathering paths. This

management, Raeder claims, is in place because of the cultural significance of the animals, and

creating this “food oasis” is their way of increasing local abundances of peccaries and ensuring

spiritual well-being (Ocampo-Raeder 2006:188-191). At the current rate of population decline of

the white-lipped peccaries, the Amazonian region stands close to losing a valuable element of

both biological and cultural diversity.

Recommendations for Future Conservation

An increase in resilience is needed from either humans or from the white-lips in order to

keep peccary populations from tending towards extinction. Seeing as recent human interactions

with the rainforest have driven peccary populations to the point where they can no longer keep

up with the demanding rate of evolution, a need for human intervention and resilience seems

essential in protecting this vulnerable species from extinction. If humans are the cause of limiting

the ability of and time for a species to respond and adapt to disturbances in the ecosystem, then

ecological resilience must be extended to our society’s responsibility to these organisms and to

the environment in which they live. A series of courses of action have already been suggested:

reintroduction programs, stricter enforcement of hunting rules in protected areas, and buffer

zones for peccaries outside of habitat fragments, but there is an important point that Ocampo-

Raeder brings about in her dissertation. The indigenous groups that depend so heavily on the

white-lipped peccaries already know a method of increasing their populations—they have been

doing it for longer than we even know. So perhaps it is time to breach that cultural barrier and

learn to work with the indigenous groups to share both western and indigenous knowledge on

conservation in a collective effort to promote both the preservation of biological and cultural

diversity.

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