Journal
of Threatened Taxa | www.threatenedtaxa.org | 26 June 2019 | 11(8): 13967–13976
On the importance of alpha behavior integrity in male Capybara Hydrochoerus
hydrochaeris (Mammalia: Rodentia: Caviidae) following immuno-contraceptive treatment
Derek Andrew Rosenfield 1 & Cristiane
Schilbach Pizzutto 2
1,2
Department of Animal Reproduction/Wildlife, Faculty of Veterinary Medicine and
Animal Science,
University
of Sao Paulo, A. Prof. Orlando Marques de Paiva 87,
Cid. Universitaria, Sao Paulo, Brazil 05508-270.
1
dro@usp.br (corresponding author), 2
crissp@usp.br
doi: https://doi.org/10.11609/jott.4747.11.8.13967-13976
Editor: Priya Davidar, Sigur
Nature Trust, Nilgiris, India. Date of publication: 26
June 2019 (online & print)
Manuscript
details: #4747 | Received 05 December 2018 | Final received 06
June 2019 | Finally accepted 11 June 2019
Citation: Rosenfield,
D.A. & C.S. Pizzutto
(2019). On the importance of
alpha behavior integrity in male Capybara Hydrochoerus hydrochaeris
(Mammalia: Rodentia: Caviidae) following
immuno-contraceptive treatment. Journal of Threatened Taxa
11(8): 13967–13976. https://doi.org/10.11609/jott.4747.11.8.13967-13976
Copyright: © Rosenfield & Pizzutto 2019. Creative Commons
Attribution 4.0 International License. JoTT allows unrestricted use, reproduction, and
distribution of this article in any medium by adequate credit to the author(s)
and the source of publication.
Funding: The project was partially funded by FAPESP, Sao Paulo, Brazil, Project Number 2016/12549-5.
Competing interests: The authors declare no competing interests.
Author
details: Derek Andrew Rosenfield is
a post-graduate researcher at the Department of Animal Reproduction (Wildlife),
Faculty of Veterinary Medicine and Animal Science (FMVZ), University of Sao
Paulo (USP), Brazil. His research focuses on wildlife population control to
mitigate human-wildlife conflicts and zoonotic disease transmission, through
reversible contraceptive methods, with emphasis on immunocontraception. Cristiane
Schilbach Pizzutto
is a professor and research supervisor at the
Department of Animal Reproduction, Faculty of Veterinary Medicine and
Animal Science (FMVZ), University of Sao Paulo (USP), Brazil. In addition, her
research focuses on animal wellbeing through environmental enrichment,
supported by her role as President of the Animal Welfare Committee, at the
State Board of Veterinary Medicine, SP, and Member of the International
Environmental Enrichment Conference Committee.
Author
contribution: DAR and CSP conceived the work, designed and conducted
the field surveys, data collection, and analysis.
Abstract:
As the human population continues to grow, habitat for
wildlife shrinks, driving fauna either into extinction or into new habitats,
which can create new problems. In
Brazil, the Capybara Hydrochoerus hydrochaeris has become a pest by invading urban and agricultural
areas. These mammals quickly multiply
owing to abundant food supply and a lack of natural predators, and they can
serve as amplifying hosts for Rickettsia rickettsii,
the pathogen of potentially life-threatening Brazilian
spotted fever. Species-specific
population management strategies that respect public opinion and consider
animal welfare are required for the effective mitigation of this tick-borne
zoonotic disease. In order to control
Capybara populations it is necessary to take into account their social
dynamics, which are centered on polygynous dominant
males with hormone-driven secondary sexual characteristics. To be a viable management tool, a
contraceptive strategy targeting these males must preserve their social status
to prevent other males from replacing them.
As part of a larger research project on the efficiency of anti-Gonadotropin-releasing
hormone (GnRH) vaccine treatment in free-ranging Capybaras, the aim of this
study was to observe the impact of this treatment on alpha male and overall
social group behavior. At the end of the 18-month-study, there were
no recorded births involving the immunized animals, and alpha male sexual
characteristics and group integrity were preserved. These results encourage the use of this
anti-GnRH vaccine as an alternative population control tool in male Capybara.
Keywords:
Agonistic behavior, Brazilian spotted fever, Gonacon, Rickettsia, secondary sexual characteristics,
wildlife population control.
[German] Abstrakt:
Mit ständiger weiterwachsender menschlicher Bevölkerung somit auch der
notwendige Lebensraum, unvermeidlich, schrumpft auch der natürliche Raum für
wildlebende Tiere, dass treibt die Fauna entweder zum Aussterben oder in neue
Lebensräume, einschließlich die von Menschen besätzten.
Dies führt unweigerlich zu Problemen auf mehreren Ebenen. In Brasilien, wird
insbesondere eine einheimische Wildtier Spezies für den Menschen immer
lästiger. Der synanthropisch heranwachsende Capybara, oder Wasserschwein (Hydrochoerus
hydrochaeris), der in seiner Natur stark proliferativ ist,
entwickelt sich zu einer Superpopulation und wird zu einer Bedrohung für die
menschliche Gesundheit, aufgrund seiner Funktion als einer der wichtigsten
Wirt-Tiere für Rickttsia rickettsii, der Pathogen für das Brasilianische Flecken
Fieber. Daher ist die Entwicklung von artengerechter Bevölkerungs-Kontrolle,
unter Beachtung der öffentlichen Meinung und die Berücksichtigung des
Tierschutzes, zur wirksamen Eindämmung von durch Zecken übertragenen Zoonose
Erkrankungen erforderlich. Ein Konsens darüber, wie die Krankheitsübertragung
des möglicherweise kontrolliert werden kann, besteht darin, die Bevölkerung des
Wirts direkt zu kontrollieren und gleichzeitig die Dynamik zu beseitigen, die die
Aufrechterhaltung des Pathogens ermöglicht. Als polygynische Gesellschaft mit einer starken hierarchischen
Organisation, die von einem dominanten Männchen aufrechterhalten wird, ist die
Beibehaltung der Integrität der hormonabhängigen sekundären Geschlechtsmerkmale
und des agonistichen Verhaltens von entscheidender
Bedeutung. Damit ein Eingriff durch Verhütungsstrategien ein wirksames
Managementinstrument in Capybara sein kann, ist es
unbedingt erforderlich, die phänotypischen und Dominanzmerkmale des Alpha-Männchens
zu erhalten. Der Verlust des dominanten Status würde den opportunistischen
Einstieg eines „Satelliten“- Männchens ermöglichen und somit das angestrebte
Ziel der Geburtenkontrolle verfehlen. Ziel dieser Arbeit war es, im Rahmen
eines größeren Forschungsprojekts zur Effizienz des Immunokontrazeptivums
Anti-GnRH (Gonacon ™) in
Wild-Capybaras die Auswirkungen dieser
Bevölkerungskontrollstrategie auf das alpha Männchen
sowie dem sozialen Verhalten der Gruppe zu untersuchen. Beobachtungen, die über
einen Zeitraum von 18 Monaten gemacht wurden, rapportieren eine Reduktion der
Geburtenrate von 100% der immunisierten Tiere unter Beibehaltung der
alpha-Merkmale des dominanten Männchens und somit die Aufrechterhaltung der
sozialen Struktur der Gruppe. Zusammenfassend lässt sich festhalten, dass die
Ergebnisse die Verwendung dieses Immunokontrazeptiva-Impfstoffs
zur Populationskontrolle in frei-lebendem Capybara
empfohlen werden kann.
[Portuguese]
Resumo: À medida que a população humana continua a crescer e
expandir seu habitat, o espaço natural para a vida selvagem diminui, levando a
fauna à extinção ou a novos habitats, incluindo áreas ocupadas por seres
humanos. Isso, inevitavelmente, gera problemas em vários níveis. No Brasil, uma
espécie nativa, em particular, está se tornando mais incômoda. A capivara sinantrópica (Hydrochoerus hydrochaeris), altamente proliferativa por natureza, atinge
superpopulações, sendo uma ameaça emergente à saúde humana já que é um dos
principais hospedeiros da Rickettsia rickettsii, patógeno da febre maculosa brasileira. Assim, o
desenvolvimento de estratégias de gestão de populações específicas de espécies,
respeitando a opinião pública e considerando o bem-estar animal são necessárias
para a mitigação eficaz dessas doenças zoonóticas
transmitidas por carrapatos. Um consenso
sobre como potencialmente conter a transmissão da doença é controlando
diretamente a população do hospedeiro, enquanto indiretamente remove a dinâmica
que permite que os patógenos sejam mantidos. Como uma sociedade polígina com forte organização hierárquica que é sustentada
por um macho dominante, a integridade das características sexuais secundárias e
do comportamento agonístico a hormônios é crucial.
Para que uma intervenção das estratégias contraceptivas seja uma ferramenta de
gestão viável, é imperativo preservar as características fenotípicas e agonísticas do macho alfa. Perder o status dominante
permitiria a entrada oportunista de um macho competitivo, consequentemente,
levando a uma falha do gerenciamento populacional pretendido. Como parte de um
projeto de pesquisa maior sobre a eficiência de um imunocontraceptivo
em capivaras de vida livre, o objetivo deste trabalho foi observar seu impacto
sobre o comportamento do macho alfa e do grupo. No final do estudo de 18 meses,
não houve registros de nascimentos envolvendo os animais imunizados.
Concomitantemente, as características do macho alfa foram preservadas e
subsequentemente a integridade do grupo. Em conclusão, os resultados encorajam
o uso desta vacina anti-GnRH como uma ferramenta
alternativa de controle populacional em capivaras machos.
Introduction
Hydrochoerus hydrochaeris, commonly known as Capybara, the
world’s largest rodent species, endemic to South America, and are habitat
generalists surviving in open grasslands and scrub vegetation. Capybaras are
semi-aquatic so stay close to water, which is used as their principal getaway
and serves as a place for thermoregulation, defecation, mating, as well as an
important food source (Mones & Ojasti 1986; Magnusson 1998; Moreira et al. 2012; Elias
2013). Intensive anthropogenic
activities have dramatically changed the landscapes and habitats where Capybara
live. With diminishing natural space and
an increase in agricultural and urban areas, these animals are re-occupying and
thriving in their human-modified habitats.
Their social structure is based on polygyny (harem),
with one dominant (alpha) male, females that are divided into dominant
(breeding females) and subordinate females, male and female juveniles, and,
depending on the season, pups. In
Brazil, a wild herd can reach up to 50 members (Macdonald 1981). Isolated Capybara, known as satellites, can
often be seen maintaining a certain distance from the main group; these are
sexually mature males forced out by the alpha male (Image 1).
Subordinate females, although sexually mature, do not
mate with the alpha male; their restraint is due to interactions with dominant
females and their social stimuli, which is believed to cause reproductive
suppression, either physically, endocrinologically, or by olfactory cues
(Maldonado-Chaparro & Blumstein 2008).
However, some subordinate females have been observed leaving their group
for short periods of time to seek out nearby satellite males to mate with, as
observed during this present study.
Due to several contributing factors, such as
the loss of natural predators, the Capybara’s ability to quickly adjust to
agricultural and urban settings, their tolerance to human presence, the
abundance of available foods, combined with their high proliferation rates,
have allowed the Capybara to become Brazil’s second most important
pest-species, the other being Wild Boar (Pedrosa et al. 2015). Under these conditions Capybaras attain large
population sizes, with herd numbers that can reach over 100 individuals which
creates traffic accidents, damage to private property, invasion of public and
private spaces, and destruction to crops, particularly corn and sugarcane
plantations (Ferraz et al. 2003; Labruna
et al. 2007; Labruna 2013; Felix et al. 2014; de
Oliveira Vieira et al. 2015; Abreu Bovo et al.
2016).
The
main concern, however, is the threat to human health as Capybara are associated
with the maintenance and spread of the tick-borne disease Brazilian spotted
fever (Portuguese: febre maculosa). Capybara are
considered an amplifying host for this emerging vector-borne zoonosis caused by
the potentially deadly bacterium Rickettsia rickettsii,
which is spread by ticks of the genera Amblyomma
sp. (Fortes et al. 2011; Labruna, 2013; Brites-Neto et al. 2015).
They fulfill five requirements to be considered a good
amplifying vertebrate host for R. rickettsia:
(1)
be abundant in the endemic area, (2) be a good host for the ticks, (3) be
susceptible to Rickettsia infection, (4) have high population growth rates, and
(5) have enough bacteremia counts to infect ticks (Labruna et al. 2009).
Although
there are other native wildlife species reported to host R. rickettsii, such as dog, horse, opossum, among others (Labruna et al. 2009; Milagres et
al. 2010), there are a number of reasons that Capybara are the major
contributing factor for R. rickettsii
infection in endemic areas. They
exclusively occupy areas close to bodies of water and move slowly, making them
conducive for ticks to infest in large numbers and
feed upon. Some tick species such as Amblyomma dubitatum
are highly specific to Capybaras and rarely feed on other host species. Humans, however, may become accidental hosts
(Guglielmone et al. 2006; Labruna
et al. 2007; Beati et al. 2013; Brites-Neto
et al. 2015).
Several
field studies and stochastic models have been developed that have reported
spotted fever transmission dynamics, postulating that birth-rate reduction not
just can directly control Capybara population growth, but potentially slow
disease transmission (Sonenshine & Mather 1994; Labruna et al. 2002; Federico & Canziani
2005; Polo et al. 2017; Polo et al. 2018; Rosenfield et al. 2019).
In an
effort to control these fast-growing super-populations, several research
projects are being conducted, seeking methods that are effective in managing
populations while conforming to environmental protection laws and public
opinion. Capybara, as it’s categorized
as Brazilian native fauna, is protected from hunting, slaughter, and abuse (Presidência da República 1981;
Rodrigues 2013).
In
Brazil, Capybara potentially reproduces all year round, however, they are
constrained by environmental factors, food availability and human impacts. As the principal breeder, the alpha male
protects the herd and mates with many females.
Focusing on the sterilization of the dominant male could be a population
control strategy of choice, provided that the procedure does not alter its
dominant status (Alho & Rondon
1987; Rodrigues 2008; Paula & Walker 2013).
Capybara are fiercely territorial, protecting harem and habitat, driving
out potential male intruders or subordinate males that attempt to challenge the
alpha male (Herrera & Macdonald 1993); thus, the importance to maintain
testosterone production which influences their secondary sexual characteristics
and dominance (agonistic) behavior. For this reason, vasectomy was considered
initially a suitable intervention as sperm conduction is interrupted, yet,
leaving the gonad function intact so a continuation of steroidogenesis is
ensured (Meira et al. 2013). If performed correctly, it is completely
effective. On the downside, the
logistics, cost, skill availability and access to the testes which is in an
intra-abdominal position, are more challenging.
The biggest dilemma, despite being considered a minimally invasive
surgical procedure, is the time for recovery.
Capybara, when injured, sick, or during labor,
distance themselves from the group until healing is complete (D.A. Rosenfield
xi.2016 – xii.2018). Observations
indicate that vasectomized males distance themselves from the group for up to
10 days, potentially allowing competitors to move in and take over,
jeopardizing the efforts to manage the population growth.
Additionally,
subordinate males are known to breed opportunistically, even as much as 40% of
the overall growth rate (Rodrigues 2008), which is initiated by subordinate
females temporarily leaving the main group (Labruna
Marcelo & Fernanda Nunes pers. comm. 20.ix.2018). In this case, an alternative method to
consider is tubal ligation (tubectomy) in all sexually mature females. The concept is analogous to the
deferentectomy procedure in males, with the intent to inhibit gamete
transmission but preserve gonadal steroidogenesis, and, hence, social behavior/group stability.
In
general, we can organize the breeding hierarchy into one alpha male and several
dominant females as the principal breeders. Subordinate females (believed to be in
reproductive suppression due to the presence of dominant females), and/or their
opportunistic mating with external (satellite) males (Fig. 1), which postulates
three distinct population control strategies:
Contraceptive
strategies
The
immuno-contraceptive treated alpha male effectively maintains agonistic conduct
and secondary sexual characteristics.
They successfully defend against potential intruders; however, the alpha
male does not mate with dominant females.
Subordinate females opportunistically and temporarily leave the group to
join nearby satellite males to mate (Fig. 2).
After the mating event, the now pregnant female returns to the group and
remains there during gestation.
Following birth, the pups are brought up in an allo-parental
manner, as commonly observed in Capybaras (Nogueira et al. 2000).
Due
to the castration, the original alpha male loses agonistic conduct and
secondary sexual characteristics.
Growing males, sexually mature, or dominant growing satellite males
challenge the alpha male, leading to his defeat and consequently driving the
ex-alpha male out of the group or even killing him (Fig. 3).
The new (untreated) dominant male will become the alpha male and restart
the mating process.
The
treated alpha male does not leave the group post-treatment and maintains alpha
associated conduct and secondary sexual characteristics. Alpha male is now infertile (Fig. 4), but the
group’s social structure is stable.
Also, treating all satellite males and all sexually mature females will
prevent opportunistic mating encounters with satellite males.
Illustrated
contraceptive strategies
In
order to find alternative contraceptive methods that would address the
weaknesses of currently employed population control strategies in Capybaras, an
intensive literature review on contraceptive methods in wildlife was
conducted. The objective was to match
most of the desired characteristics of a contraceptive agent, which would
include antifertility effectiveness of more than 90%; long-term effect of more
than 12 months; with very little to no adverse effects (physiological/behavioral).
Especially, considering a polygynous society, like Capybara, the
importance of maintaining the dominant male’s agonistic behavior
is supreme. Furthermore, it is
applicable in both the sexes; represents no risks to pregnant females;
potentially reversible; easy and safe application; allows for remote drug
delivery (long-distance darting); does not provoke environmental pollution;
does not have contraceptive effects when entering the food-chain, and lastly,
is economically viable and available (Figs. 2–4).
The
anti-GnRH vaccine GonaCon™ was selected as it
conformed to most of these conditions (Asa 2005; Gionfriddo
et al. 2008; Ajadi & Oyeyemi
2015; Rosenfield 2016). The objective of
this research was to demonstrate the effectiveness of an anti-GnRH
immuno-contraceptive (Gonacon™) in reducing
population growth in the capybara without interfering with the behavioral characteristics of the alpha male.
Materials & Methods
Location
A
large man-made water pool (Olympic Lake, Portuguese: Raia
Olimpica) surrounded by diverse vegetation and
extended grassy areas, used for the university’s aquatic sports activities, was
selected in Sao Paulo (Image 3). The environmental conditions are very similar
to the natural Capybara habitats, allowing for a unique opportunity to observe
free-ranging Capybaras in an open confined setting.
Identifying
males
At
first sight, the urogenital apparatus is not easily distinguishable between
male and female Capybara, as the male penis is situated within a large
anogenital invagination. In sub-adult
males, gender can be confirmed by palpation and exposure. Capybara alpha males have specialized
androgen-driven secondary sexual characteristics (SSC), such as a prominently
developed nasal and perianal glands for scent-marking (Image 2a,b).
The testes, in immature males, are located subcutaneously in the
inguinal region, whereas in dominant males, they migrate from the inguinal
region towards the area of the inner/upper thigh, becoming slightly visible
(Image 2c).
Veterinary
intervention
Two
groups were selected for the study and were based on their population size and
pest status: Group 1 consisted of more
than 40 individuals and Group II of seven individuals. The socio-sexual and reproductive behavior of male and female Capybaras were recorded for
approximately 100 hours pre- and ˃120 hours post-treatment using the continuous
focal observation method (Martin & Bateson 2007) between June --2016 --and
December 2018.
In
Group I, three individuals (male n=1, female n=2), and in group II, six
individuals (male n=2, female n=4) were treated with the anti-GnRH vaccine GonaCon™. The
vaccine was administered intramuscularly in the larger muscle group of the hind
leg. The rest of the population served
as control.
This
project-specific ethogram (Table 1) was used to assist in identifying any
treatment-associated alterations, allowing an interpretation of cues of a successful
antifertility method and the integrity of the alpha male‘s agonistic behavior. This is
essential for maintaining the group’s social stability and preventing an
intruder from mating, and hence, providing an appropriate population growth
management tool.
Contraceptive
effect analysis
As
part of the evaluation process of the anti-fertility effect, steroid-hormone, spermogram, biometry, and testicular morphology were
employed. At the end of the study
period, males were hemi-castrated for further histological investigation of the
testicular parenchyma. These specific
findings are submitted for publishing elsewhere.
Results
Effects
of treatment
The
immunized alpha males showed oligospermia, compared to control, while their
agonistic behavior and secondary sexual
characteristics were preserved (Tables 1 & 2).
Discussion
The
leadership dynamics observed of all involved males was very compelling, as it
proved that the immuno-contraception was effective in rendering the treated
males infertile, while concurrently, preserved their alpha male behavior, and thereby the group’s integrity. Confirmed by the behavioral
observations made of an untreated sexual mature male, used as the control
variable, demonstrated during involved transitional dynamics the take-over of a
leader-less group as the new alpha male, consequently producing offspring.
Positive
antifertility effects of the immuno-contraceptive was confirmed in similar
studies and in various species; however, where the findings differ are the
observations that state the loss of agonistic behaviors
in males (Snape at al. 2011; Donovan et al. 2013; Doughty et al. 2014) while
others report no significant changes (Massei et al.
2008; Young, 2018), including the present work.
Also
important is the fact that the treated animals did not distance themselves from
the group for recovery, hence, preventing any opportunity for a satellite male
to invade.
Noteworthy,
alpha males, given the right circumstance, would leave their group in order to
take over a group with a larger number of females, as observed twice.
There
were no significant phenotypic or behavioral
alterations, nor any pathological adverse effects in the treated animals. Although the treated alpha males were
considered infertile, their secondary sexual characteristics and agonistic behaviors appeared to be preserved, as well as the groups’
overall social integrity, which is an important key fact to successfully
managing the population of this species, and exceeded all minimum expectations.
Other
currently considered male fertility strategies, such as castration and
vasectomy, which are 100% effective and do have their merits when employed in the
right situation, seem less adequate when considering large-scale intervention
in the field, considering logistics, as well as animal well-being.
Furthermore,
as the findings suggest, injured or sick individuals tend to retreat from the
group until recovered, which can take several weeks, representing a window of
opportunity for a fertile rival male to take over the group, undoing any
population control attempt.
In
regard to the relevance to public health, specifically for Brazil and spotted
fever, based on a stochastic model (Polo et al. 2017), that indicated a
birth-rate reduction of ≥ 90%, the etiological agent of the tick-borne zoonotic
disease, hypothetically, could be controlled after two years of intervention,
utilizing the alternative population control method for Capybaras described in
this work.
The
observations conducted over the study period of 18 months suggest that the
birth rate reduction needed to directly manage a Capybara population, and
indirectly the dynamics involved in maintaining and spreading R. rickettsii, could be achieved.
Conclusion
When
it comes to population control, no one solution fits all situations. Each is unique and requires a specific study
to choose the most appropriate solution.
In free-ranging Capybaras, being able to treat the alpha male, satellite
males, as well as all dominant females, seems to be the most promising method
for controlling their population growth with the highest success rate. Nevertheless, it is important to understand
that all efforts are temporary, and in order to maintain functioning population
management, this method must be practiced continuously.
Table
1. Experimental interventions and outcomes. (PDB: preserved dominant behavior; SSC: secondary sexual characteristics).
|
Group
no. |
Target |
Intervention |
Result |
Remarks |
|
1 |
Alpha male |
Immunised |
Oligospermia PDB
(driving out any male invader) Preserved
SSC No
offspring |
After
vaccination, male maintained with the group (no recovery period). Animal died
through acute cecal tympany (sever dilation of the
cecum, provoked by the failure to release gas). |
|
2 |
Alpha male |
Immunised |
Oligospermia PDB Preserved
SSC No
offspring |
After
vaccination, male maintained with the group (no recovery period) |
|
3 |
satellite
male control male |
No
intervention |
Produced
offspring |
Males mated
with females from group 1 and 2, that left the group temporarily. In the
absence of a dominant male, satellite males will take over the group. |
Table
2. Ethogram of recorded behavior.
|
Ethogram Alpha
Male |
|
Observations Control
Alpha Male |
Treated
Alpha Male |
Satellite
Male |
|
Behavior |
Description
of behavior |
|
|
|
|
Any visual
treatment-related discomfort |
Separating
from the group immediately after treatment; Apathetic; no foraging; allowing
an intruder to get close to the group/females |
n/a |
The treated
alpha did not distance himself at any moment post-treatment. All alpha
related conducts remained intact. |
n/a |
|
Vigilance |
Alpha male
remained at a certain distance in a sitting or ventral decubitus position
watching over the group |
Confirmed |
Confirmed |
Observing
the group. Infrequent contact with subordinate females |
|
Relocation |
Leading
group to a different location (for better foraging grounds, or for safety) |
Confirmed |
Confirmed |
n/a |
|
Scent
marking |
Marking
territory by rubbing with nasal gland surface or perianal gland surface over
stationary objects; urinating onto the ground |
Confirmed |
Confirmed |
Confirmed |
|
Courtship behavior |
Seeking
physical contact with females. Testing receptivity for mating by sniffing
urogenital region, pushing snout into female’s flank, or snout. Putting head
onto female’s dorsal pelvic region. |
Confirmed |
Frequent
contact (sniffing) but no mating conduct |
Observed
when approached by a female |
|
Mating |
Male
continuously follows the female. Frequent mounting attempts by placing upper
torso onto female’s lumbar/pelvic region, performing a thrusting motion with
the pelvis. |
Confirmed |
Not
observed. Possible attempts, but infertile male. |
Observed
when approached by a female |
|
Agonistic
(aggressive) behavior |
Attacking,
fighting, and chasing the intruder |
Confirmed |
Confirmed |
n/a |
For
figures & images – click here
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