Amphibious communication with sound in hippos, Hippopotamus amphibius
Section snippets
Methods
I made the recordings and observations reported here from June to August 1992 during the dry season on the Ruaha River in Ruaha National Park in Tanzania, and in July 1997 on the Olifants River in Kruger National Park in South Africa. At Ruaha, I worked at four sites that included seven territories. I concentrated on one site with two adjacent territories, each about 100 m long and 70 m wide. Above and below this site, the river becomes shallow (less than a metre deep) and turbulent, so
Results
When the hippos were in the water during the socially active period late in the day, they were underwater (eyes and ears and most or all of their bodies) 77% of the time. Percentage of time spent underwater varied with time, decreasing somewhat until the hippos left the water to graze (Fig. 1). It was also during this period that they were most vocal (Karstad & Hudson 1986).
When hippos were in the water, their sounds were variously audible in air or water or both simultaneously (sounds were
Discussion
Hippo sounds made in the amphibious position are clearly audible in both air and water. Both sounds, however, are not necessarily used for communication. The underwater component, for example, may be an inevitable physical consequence of a sound made when the body is partially underwater; or the amphibious position may provide an efficient path for underwater broadcast with the aerial component as a by-product. Evidence presented here, however, shows that hippo receivers react to both the
Acknowledgments
I thank Darlene Ketten, Charles Repenning and Kenneth Norris for their technical assistance and helpful suggestions. I am grateful to Katherine Payne and David Mellinger for reviewing the manuscript, and to my students for their help in collecting and analysing the data. I also thank Tanzanian National Parks and Kruger National Park for their cooperation and permission to work in the parks. This work was supported by Sea World Inc. and Busch Gardens, Tampa, Florida; The Explorers Club, New
References (36)
- et al.
Sound production by the grey whale and ambient noise levels in Laguna San Ignacio, Baja CA sur, Mexico
- et al.
Shallow water propagation of the toad fish mating call
Comparative Biochemical Physiology
(1983) A contribution to the physiology of bone conduction
Acta Otolaryngology, Supplement
(1938)Big talkers
Wildlife Conservation
(1994)Some underwater sounds of the hippopotamus (H. amphibius)
Marine and Freshwater Behaviour and Physiology
(1997)- et al.
Canary 1.2 User's Manual
(1995) - et al.
Functional morphology and homology in the odontocete nasal complex: implications for sound generation
Journal of Morphology
(1996) The Hippos
(1999)- et al.
Sound propagation in shallow water: implications for acoustic communication by aquatic animals
Bioacoustics
(1993) - et al.
Social signals and behavior of adult alligators and crocodiles
Bulletin of the American Museum of Natural History
(1978)
More DNA support for a Cetacea/Hippopotamidae clade: the blood-clotting protein gene γ-fibrinogen
Molecular Biological Evolution
The underwater audiogram of the West Indian manatee (Trichechus manatus)
Journal of the Acoustical Society of America
Social organization and communication of riverine hippopotami in southwestern Kenya
Mammalia
Low frequency amphibious hearing in pinnipeds: methods, measurements, noise and ecology
Journal of the Acoustical Society of America
Low-frequency aerial hearing of a harbor porpoise (Phocoena phocoena)
The marine mammal ear: specializations for aquatic audition and echolocation
Structure, function and adaptation of the manatee ear
Social organization and behavior of Hippopotamus amphibious
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Artiodactyl vocalization
2020, Neuroendocrine Regulation of Animal Vocalization: Mechanisms and Anthropogenic Factors in Animal CommunicationEvolution of the MC5R gene in placental mammals with evidence for its inactivation in multiple lineages that lack sebaceous glands
2018, Molecular Phylogenetics and EvolutionCitation Excerpt :These features have been interpreted as aquatic specializations that evolved on the stem lineage to Cetancodonta (Cetacea + Hippopotamidae) (Fig. 1A; Gatesy et al., 1996, 2013; Geisler and Theodor, 2009). In addition to the loss of sebaceous glands and hair reduction, other features that have been linked to a water-dependent ecology in the common ancestry of Cetancodonta include underwater communication and hearing, underwater nursing, underwater birth, loss of scrotal testes, and dense limb bones that increase specific density to overcome buoyancy (Gatesy, 1997; Barklow, 2004; Coughlin and Fish, 2009; Spaulding et al., 2009; Boisserie et al., 2011; Gatesy et al., 2013; Tsagkogeorga et al., 2015). Hippopotamids (represented by Hippopotamus amphibius) and cetaceans (represented by Delphinus delphis [common dolphin]) also display increased production and storage of free fatty acids in the vital epidermis (i.e., below the stratum corneum), although in hippopotamids this storage is largely intracellular whereas in odontocetes most of the free fatty acids occur in intercellular spaces (Meyer et al., 2012).
Anatomy of Underwater Sound Production With a Focus on Ultrasonic Vocalization in Toothed Whales Including Dolphins and Porpoises
2018, Handbook of Behavioral NeuroscienceCitation Excerpt :In addition, some deep diving seals have developed tracheal membranes and valves that may also vibrate to generate underwater sounds (see review in Reidenberg & Laitman, 2010). Vocalization both in air and underwater has also been observed in the hippopotamus (Barklow, 2004). As in other aquatic mammals, vibrations of laryngeal vocal folds are used for generating these sounds, and transmission to air follows essentially a terrestrial vocalization mechanism.
Infrasonic and Ultrasonic Hearing Evolved after the Emergence of Modern Whales
2017, Current BiologyCitation Excerpt :Of note, two key characters related to high-frequency hearing in cetaceans ([15]; indicated in red in Figure 3)—a large spiral ganglion (>4% of the area of the cochlear window) and a long SBL (>20% of the cochlear canal)—are also found in several terrestrial taxa (e.g., Ruminantia, Diacodexis or Cebochoeridae). The greatest number of character states associated with low-frequency sensitivity (indicated in blue in Figure 3) is found in Mysticeti and in modern land artiodactyls with the lowest recorded hearing range, such as Suoidea (Sus), Ruminantia (Bos), and Hippopotamoidea (Hippopotamus) [22, 25]. Convergent acquisitions of characters associated with low-frequency sensitivity occur in these four major artiodactyl clades.
The Origin of High-Frequency Hearing in Whales
2016, Current BiologyCitation Excerpt :Discriminant function analyses were used to generate classification rates for extant taxa using two (low and high frequency) and three (low frequency, high frequency, and terrestrial) categories. Extant whales were classified according to hearing data from the literature [11], while hippopotamids were treated as either low frequency [10] or terrestrial, depending on the number of categories used. Extant taxa were classified with 100% accuracy into each category, and separate analyses were used to determine which category fossil whale taxa belonged to.