16) Physiologic data
Thermoregulation of the hippopotamus was studied by Cena (1964). Macdonald & Hartman (1983) dissected the stomachs of adult and neonatal pygmy hippos, finding them to be four-chambered. Griner (1983) specified only three chambers. Nevertheless, the animals do not ruminate. The renal anatomy of adult and neonatal pygmy hippopotamus was described in great detail by Maluf (1994). Rouille et al. (1988) studied the occurrence of vasopressin in river hippopotamus and in collared peccary. They found arginine vasopressin but no lysine vasopressine in these species, contrary to the finding in Suidae. In a molecular study of milk casein, Gatesy et al. (1996) found the structure to be closer to cetacea than to other artiodactyl species, confirming the close relationship of whales and hippos. From these data, the authors suggested that an intermediate fossil may so far be "missing". The means of immobilization of the Nile hippopotamus (9 animals) was described by Ramsay et al. (1998). One death occurred from apnea. Flach et al. (1998) removed a dead fetus from a pygmy hippo by Cesarean section with recovery of the dam. Using specific antibodies to retinal cone visual pigments, Peichl et al. (2001) demonstrated the absence of S-cones in odontocetes and five species of seals, but affirmed their presence in pygmy hippopotamus (and other terrestrial animals). This indicated to the authors an absence of color vision in marine mammals. Eltringham (1999) has most comprehensively detailed the anatomy, known physiology, distribution, and general problems affecting hippopotamuses.
17) Other resources
Cell strains of fibroblast are available of both species from CRES at the San Diego Zoo by contacting Dr. Oliver Ryder at oryder@ucsd.edu.
18) Other remarks - What additional Information is needed?
The discrepancy of the number of umbilical cord blood vessels is troubling and needs further study. Also, early specimens, preferably implanted placentas, should be described. There is too little endocrine information and the absence of binucleated trophoblastic cells is of interest. Thus, is there any placental lactogen produced during pregnancy, as in other ungulates? Ascending infection, as seen in equines, needs to be paid attention to.
Acknowledgement
The animal photographs in this chapter come from the Zoological Society of San Diego.
References
Amoroso, E.C., Hancock, N.A. and Kellas, L.: The foetal membranes and placenta of the hippopotamus (Hippopotamus amphibius (Linnaeus). Proc. Zool. Soc. London 130:437-454, 1958.
Antonius, E.: Lexikon ausgerotteter Vögel und Säugetiere. Natur und Tier - Verlag, Munster, 2003.
Arnason, U., Gullberg, A., Gretarsdottir, S., Ursing, B. and Janke, A.: The mitochondrial genome of the sperm whale and a new molecular reference for estimating eutherian divergence dates. J. Mol. Evol. 50:569-578, 2000.
Baer, K.E.v.: Ueber Entwicklungsgeschichte der Thiere. 1837.
Bush, M., Lemken, R. and Moore, J.A.: Prolapsed uterus in a pigmy hippopotamus. J. Amer. Vet. Med. Ass. 161:651, 1972.
Cena, K.: Thermoregulation in the hippopotamus. Int. J. Biometeorol. 8:57-60, 1964.
Dauth, J., Dreyer, M.J., Raubenheimer, E.J., Lemmer, L.B. and de Vos, V.: Blood lead concentrations in hippopotami (Hippopotamus amphibius) in the Kruger National Park. J.S. Afr. Vet. Assoc. 59:153-154, 1988.
Eltringham, S.K.: The Hippos. Academic Press, London. 1999.
Eschricht, D.F.: De organis, quae respirationi et nutritioni foetus mammalium inserviunt: anniversaria (Schultziana, Havniae). 1837 {quoted from Ludwig, 1968].
Flach, E.J., Furrokh, I.K., Thornton, S.M., Smith, J., Parkyn, J.P. and Campbell, E.J.: Caesarean section in a pygmy hippopotamus (Choeropsis liberiensis) and the management of the wound. Vet. Rec. 143:611-613, 1998.
Gatesy, J., Hayashi, C., Cronin, M.A. and Arctander, P.: Evidence from milk casein genes that cetaceans are close relatives of hippoptamid artiodactyls. Mol. Biol. Evol. 13:954-963, 1996.
Gerneke, W.H.: The chromosomes and neutrophils nuclear appendages of Hippopotamus amphibius Linnaeus 1758. Onderstepoort J. Vet. Res. 32:181-186, 1965.
Gotch, A.F.: Mammals - Their Latin Names Explained. Blandford Press, Poole, Dorset, 1979.
Graham, L.H., Reid, K., Webster, T., Richards, M. and Joseph, S.: Endocrine patterns associated with reproduction in the Nile hippopotamus (Hippopotamus amphibius) as assessed by fecal progestagen analysis. Gen. Comp. Endocrinol. 128:74-81, 2002a.
Graham, L.H., Webster, T., Richards, M., Reid, K. and Joseph, S.: Ovarian function in the Nile hippopotamus and the effects of Depo-Provera administration. Reprod. Suppl. 60:65-70, 2002b.
Griner, L.A.: Pathology of Zoo Animals. Zoological Society of San Diego, San Diego, California, 1983.
Hasegawa, M. and Adachi, J.: Phylogenetic position of cetaceans relative to artiodactyls: reanalysis of mitochondrial and nuclear sequences. Mol. Biol. Evol. 13:710-717, 1996.
Hediger, H.: Die Hippomanes der Hippopotamiden. Zool. Garten 26:321-336, 1962.
Hsu, T.C. and Benirschke, K.: An Atlas of Mammalian Chromosomes. Volume 10, Folio 507, 1977. Springer-Verlag, N.Y.
Jones, M.L.: Longevity of captive mammals. Zool. Garten 52:113-128, 1982.
Keibel, F.: Ueber den Nabelstrang des Nilpferdes. Anat. Anzeiger 8:497-504, 1893.
Kleineidam, R.G., Pesole, G., Breukelman, H.J., Beintema, J.J. and Kastelein, R.A.: Inclusion of cetaceans within the order Artiodactyla based on phylogenetic analysis of pancreatic ribonuclease genes. J. Mol. Evol. 48:360-368, 1999.
Kuttin, E.S., Loupal, G., Kohler, H. and Supperer, R.: Coccidiosis of the placenta in a hippopotamus (Hippopotamus amphibius). 29:153-159, 1982.
Lang, E.M.: Das Zwergflusspferd Choeropsis liberiensis. A Ziemsen Verlag, Wittenberg Lutherstadt, 1975.
Laws, R.M. and Clough, G.: Observations on reproduction in the hippopotamus, Hippopotamus amphibius Linn. Pp. 117-140, in, I.W. Rowlands, ed.: Comparative Biology of Reproduction in Mammals. Sympos. Zool. Soc. London # 15. Academic Press, London, 1966.
Lochte, Th.: Untersuchungen an Haaren eines neugeborenen Nilpferdes und eines Flusspferdes. Zool. Garten 18:119-124, 1951.
Ludwig, K.S.: Zur vergleichenden Histologie des Allantochorion. Revue Suisse Zool. 75:819-831, 1968.
Macdonald, A.A. and Bosma, A.A.: Notes on placentation in the Suina. Placenta 6:83-91, 1951.
Macdonald, A.A. and Hartman, W.: Comparative and functional morphology of the stomach in the adult and newborn pigmy hippopotamus (Choeropsis liberiensis). J. Morphol. 177:269-276, 1983.
Madsen, O., Willemsen, D., Ursing, B.M., Arnason, U. and de Jong, W.W.: Molecular evolution of the mammalian alpha 2b adrenergic receptor. Mol. Biol. Evol. 19:2150-2160, 2002.
Maluf, N.S.: Renal anatomy of the pigmy hippopotamus (Choeropsis liberiensis): an overview. Anat. Histol. Embryol. 23:189-206, 1994.
Mwase, M., Almli, B., Sivertsen, T., Musonda, M.M. and Flaoyen, A.: Hepatic and renal concentrations of copper and other trace elements in hippopotami (Hippopotamus amphibius L) living in and adjacent to the Kafue and Luangwa Rivers in Zambia. Onderstepoort J. Vet. Res. 69:207-214, 2002.
Nikaido, M., Rooney, A.P. and Okada, N.: Phylogenetic relationships among certiodactyls based on insertion of short and long interspersed elements: Hippopotamuses are closest extant relatives of whales. Proc. Natl. Acad. Sci. USA 96:10261-10266, 1999.
Nomura, O. and Yasue, H.: Genetic relationships among hippopotamus, whales, and bovine based on SINE insertion analysis. Mamm. Genome 10:526-527, 1999.
Nowak, R.M.: Walker's Mammals of the World. 6th ed. The Johns Hopkins Press, Baltimore, 1999.
Oliver, R.C.D.: Aspects of skin physiology in the Pigmy hippopotamus Choeropsis liberiensis. J. Zool. London 176:211-213, 1975.
Oliver, W.L.R., ed. Pigs, Peccaries, and Hippos. IUCN/SSC Pigs & Peccaries, and Hippo Specialist Groups. IUCN Gland, Switzerland, 1993.
Peichl, L., Behrmann, G. and Kroger, R.H.: For whales and seals the ocean is not blue: a visual pigment loss in marine mammals. Eur. J. Neurosci. 13:1520-1528, 2001.
Pickles, G.: Injuries by wild animals in the African bush. J.R. Army Med. Corps 133:159-160, 1987.
Pitchford, R.J. and Visser, P.S.: Schistosoma Weinland, 1958 from Hippopotamus amphibius Linnaeus, 1758 in the Kruger National Park. Onderstepoort J. Vet. Res. 48:181-184, 1981.
Ramsay, E.C., Loomis, M.R., Mehren, K.G., Boardman, W.S., Jensen, J. and Geiser, D.: Chemical restraint of the Nile hippopotamus (Hippopotamus amphibius) in captivity. J. Zoo Wildl. Med. 29:45-49, 1998.
Reddacliff, L.A., Kirkland, P.D., Hartley, W.J. and Reece, R.L.: Encephalomyocarditis virus infections in an Australian zoo. J. Zoo Wildl. Med. 28:153-157, 1997.
Robinson, P.T.: Wildlife trends in Liberia and Sierra Leone. Oryx 11:117-122, 1971.
Rouille, Y., Chauvet, M.T., Cauvet, J., Acher, R. and Hadley, M.E.: The distribution of lysine vasopressin (lysipressine) in placental mammals: a reinvestigation of the Hippopotamidae (Hippopotamus amphibius) and Tayassuidae (Tayassu angulatus) families. Gen. Comp. Endocrinol. 71:475-483, 1988.
Saikawa, Y., Hashimoto, K., Nakata, M., Yoshihara, M., Nagai, K., Ida, M. and Komiya, T.: The red sweat of the hippopotamus. The red and orange pigments in the secretion account for its protective properties. Nature 429:363, 2004.
Teuscher, R.: Anatomische Untersuchungen über die Fruchthüllen des Zwergflusspferdes. Z. Anat. 555, 1937.
Tsuji, S., Kato, H., Matsuoka, Y., Fukushima, T., Nanjoh, I., Amano, T. and Namikawa, T.: Phylogenetical and ontogenetical studies on the molecular weight heterogeneity of bovine serum transferrin. Biochem. Genet. 22:1127-1143, 1984.
Turner, W.: On the structure of the diffused, the polycotyledonary and the zonary forms of placenta. J. Anat. Physiol. 10:127-177, 1876.
Ursing, B.M. and Arnason, U.: Analyses of mitochondrial genomes strongly support a hippopotamus-whale clade. Proc. Royal Soc. London B Biol. Sci. 265:2251-2255, 1998.
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