Hippopotamidae (Hippopotamus)

Walzer, Chris; Stalder, Gabrielle

doi:10.1016/b978-1-4557-7397-8.00059-1

Cited by 5 publications

(4 citation statements)

References 35 publications

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“…Therefore, comparisons between animals from natural habitats and zoos ( Figs 18 and 20 ), and with respect to the growth of the skull and teeth between the sexes ( S23-S26 Figs in S1 File ), were not feasible with any confidence. Our anecdotal observation that dental wear does not appear to be particularly pronounced in zoo animals matches the absence of reports that zoo hippos are susceptible to excessive wear [ 53 ]–only to excessive incisor or canine growth. Finally, although some skulls of juvenile animals were included in our study ( S30-S38 Figs in S1 File ), we did not assess at what age the constraining effect of the canines and the incisors on transversal chewing should become pronounced.…”

Section: Discussionsupporting

confidence: 86%

“…This mechanism appears intuitive for the canines, whose wear facets are in constant, opposing contact, and in which the wear facet represents the tip of the growing tooth. In hippos, it has been observed repeatedly that the loss of a canine leads to the uncontrolled growth of its antagonist, or that a mispositioned canine that does not reach contact with its antagonist, may grow excessively [ 29 , 46 , 49 , 53 , 60 , 61 ].…”

Section: Discussionmentioning

confidence: 99%

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Chewing, dentition and tooth wear in Hippopotamidae (Hippopotamus amphibius and Choeropsis liberiensis)

Avedik,

Clauss

2023

PLoS ONE

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Among mammals, hippopotamids (‘hippos’) have been described as the species with the lowest chewing efficacy despite elaborate enamel folds on the occlusal surface or their cheek teeth, which was hypothesized to result from the lack of a grinding chewing motion. We investigated the chewing and dentition of the two extant hippo species, the common hippo (Hippopotamus amphibius) and the pygmy hippo (Choeropsis liberiensis), making (video) observations of live animals and gathering data on museum specimens (n = 86 H. amphibius and 26 C. liberiensis skulls). Hippos have a low degree of anisodonty (differences in width between maxillary and mandibular cheek teeth) and anisognathy (difference in width between the upper and the lower jaw), corresponding to a mainly orthal (up-and-down) chewing motion. The two hippo species differ slightly, but distinctively, in their anterior dental morphology and chewing mode. In both species, the canines do not completely prevent a lateral jaw movement but would, in theory, permit this movement until the mandibular canines get into contact with the maxillary protruding snout. This movement is only realized, to a small extent, in pygmy hippos, leaving distinct wear traces on their incisors and creating relatively wider wear facets on the maxillary canines. In common hippos, the interlocking upper and lower incisors prevent lateral jaw movement. Corresponding contact wear facets are evident on the medial aspect of the upper, and on the lateral aspect of the lower incisors–unless museal reconstructions mispositioned these teeth. If these facets are interpreted as an indication for a relic of a lateral jaw movement that was probably more prominent in hippo ancestors, i.e. if we assume that hippos evolved orthal chewing secondarily, several other characteristics of hippos can be explained, such as a low degree of hypsodonty (in the absence of distinct attrition due to a grinding chewing movement), a secondary loss of complexity in their enamel schmelzmuster, a secondary evolution of a wide mouth gape, a reduction in anisodonty compared to their ancestors, and the evolution of a bilaterally symmetrical (‘trifoliate’) enamel folding pattern on the molar occlusal surface from an ancestral bunoselenodont condition. As an underlying driving force, selection for intraspecific combat with canines and incisors, necessitating a wide gape and a rigid jaw, has been suggested.

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Section: Discussionsupporting

confidence: 86%

Section: Discussionmentioning

confidence: 99%

Chewing, dentition and tooth wear in Hippopotamidae (Hippopotamus amphibius and Choeropsis liberiensis)

Avedik,

Clauss

2023

PLoS ONE

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“…Anesthetic deaths primarily occurred in adults ( n = 13/15), likely because anesthetic procedures are uncommon in neonates and juveniles. The majority of these mortalities were prior to the implementation of newer, multi‐modal anesthetic protocols with improved safety and efficacy compared to ultra‐potent opioids [Bouts et al, ; Walzer and Stalder, ]. Additionally, the animals were often already debilitated at the time and required anesthesia for diagnostics and treatments, making an anesthetic procedure inherently more risky.…”

Section: Discussionmentioning

confidence: 99%

A retrospective analysis of mortality in captive pygmy hippopotamus (Choeropsis liberiensis) from 1912 to 2014

Flacke

Tkalčić

Steck³

et al. 2016

Zoo Biology

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The pygmy hippopotamus (Choeropsis liberiensis) is an IUCN Red List Endangered species (CITES Appendix II) that has been housed in zoological collections since 1912. As wild populations continue to decline throughout the species' range, successful ex situ breeding and management, including an understanding of morbidity and mortality, are of utmost importance. This study is the first comprehensive review of mortality data from the captive population since 1982 and significantly expands on previous analyses. We solicited necropsy reports from 129/187 zoological institutions worldwide that currently or previously held pygmy hippos and received data for 404 animals (177 ♂, 220 ♀, 7 undermined sex), representing 43% of pygmy hippos that have died in captivity. Mortality in neonates was primarily due to perinatal causes (51.8%-stillbirth, failure to thrive, weakness, poor suckling reflex, maternal neglect) or parent-inflicted trauma (28%). Common causes of mortality in adult and geriatric animals included cardiovascular disease (16%), degenerative musculoskeletal conditions (10%), obstructive gastrointestinal disease (9%), and renal insufficiency (13%), sometimes associated with advanced polycystic kidney disease (PKD). Although not the direct cause of mortality, a number of adult and geriatric pygmy hippos were also overweight to obese. Infectious causes of mortality in included leptospirosis and encephalomyocarditis virus, the latter usually presenting as acute death due to cardiovascular demise. This comprehensive overview presents a useful guide for recommendations in preventative veterinary care and for improved husbandry and management of pygmy hippos in captivity. Zoo Biol. 35:556-569, 2016. © 2016 Wiley Periodicals, Inc.

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“…Actualmente existen dos especies de la familia Hippopotamidae: el pequeño y raro hipopótamo pigmeo (Choeropsis liberiensis) y el hipopótamo común (Hippopotamus amphibius) abundante y de mayor tamaño 1,2 . Ambas muestran adaptaciones fisiológicas marcadas para un estilo de vida anfibio.…”

Section: Introductionunclassified

Estado actual de los hipopótamos (Hippopotamus amphibius) en Colombia: 2018

Buriticá

Guerra

2018

Ces. Med. Vet. Zootec.

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En el año 1985, el narcotraficante Pablo Escobar ingresó a Colombia entre dos y seis ejemplares juveniles de hipopótamos que, con el paso de dos décadas, se reprodujeron y movilizaron por la zona geográfica del Magdalena Medio. En la actualidad se cree que podría haber entre diez y treinta ejemplares libres en inmediaciones del río Magdalena y unos sesenta individuos en total en el país. Los hipopótamos en Colombia son animales exóticos e introducidos, y con el tiempo fueron clasificados como especie invasora ya que su presencia representa riesgos ambientales al competir con especies nativas. Algunos de los efectos comprenden la alteración de hábitat, la perturbación de los procesos ecosistémicos y la desestabilización de los sistemas ambientales. Las medidas para su control que requieren la destinación de grandes presupuestos para la captura, control de natalidad, mantenimiento en cautiverio; o acciones socialmente cuestionables como la eutanasia, deberían ser establecidas de manera inmediata pues los recursos biológicos nativos, hidrobiológicos y pesqueros podrían verse afectados por culpa de esta especie invasora.

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Hippopotamidae (Hippopotamus)

Cited by 5 publications

References 35 publications

Chewing, dentition and tooth wear in Hippopotamidae (Hippopotamus amphibius and Choeropsis liberiensis)

Chewing, dentition and tooth wear in Hippopotamidae (Hippopotamus amphibius and Choeropsis liberiensis)

A retrospective analysis of mortality in captive pygmy hippopotamus (Choeropsis liberiensis) from 1912 to 2014

Estado actual de los hipopótamos (Hippopotamus amphibius) en Colombia: 2018

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