Body temperature and basking behaviour of Nile crocodiles (Crocodylus niloticus) during winter

Downs, Colleen T.; Greaver, Cathy; Taylor, R. H.

doi:10.1016/j.jtherbio.2008.02.001

Cited by 38 publications

(24 citation statements)

References 29 publications

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“…This behavioral thermoregulation by moving in and out of the water is consistent with the previous studies for the same species (Molina and Sajdak 1993;Verdade et al 2006) and for the Nile crocodile (C. niloticus) (Downs et al 2008).…”

Section: Discussionsupporting

confidence: 92%

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Thermoregulation in captive broad-snouted caiman (Caiman latirostris)

et al. 2014

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Background: Crocodilians are ectothermic animals. For this reason, the environmental temperature has substantial effects on their physiology and behavior. The thermoregulatory behavior of these animals involves the selective use of different types of environments. This behavior enables them to reach the temperature level for their metabolic activities. This study aimed to determine the influence of sex, body size, and reproductive stage on the body temperature (T b ) of adult broad-snouted caiman (Caiman latirostris) in captivity. Thermal sensors were surgically implanted in the peritoneal cavity of 16 adult females and 4 adult males and programmed to register T b hourly during 6 months. Results: The diel T b pattern of the broad-snouted caiman reflected the variation among the microenvironmental temperatures used by the species (water surface, pool bottom, and ground). The sex of the animals had influence on their T b , but body size did not. Reproductive females had higher T b than non-reproductive females during October to early November. It is possible that this difference is a result of the ovulation period of the species. Sick animals appeared to show behavioral fever. Conclusions:The results of the present study suggest that several factors can affect the T b of adult broad-snouted caiman in captivity. Future studies should focus on the possible effect of thermoregulatory behavior on individuals' growth rate and reproductive performance.

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Section: Discussionsupporting

confidence: 92%

“…In addition, in this study, we found no relationship between body mass and snout-vent length and T b . Similar patterns have been previously described for crocodilians (Diefenbach 1975a;Downs et al 2008;Smith 1979). However, future studies should include a broader range of body sizes, as well as different periods of the year.…”

Section: Discussionsupporting

confidence: 87%

Thermoregulation in captive broad-snouted caiman (Caiman latirostris)

et al. 2014

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“…Indeed, evidence indicates a low tolerance of C. acutus to water salinity (Mazzoti & Dunson 1989), particularly in juveniles (Dunson 1970;Evans & Ellis 1977). Similarly, habitat selection by crocodilians may refl ect thermal preferences for physiological needs (Downs et al 2008;Stuebing et al 1994), with still-growing crocodiles likely to prefer hot environments due to increased growth rates at higher temperatures (Mazzoti & Brandt 1994;Pérez & Escobedo-Galván 2009). Finally, relative humidity is known to limit evaporative water loss in reptiles (Winne et al 2001;Brown & Shine 2002;Nicholson et al 2005), which may explain the higher abundance of C. acutus in areas of higher relative humidity.…”

Section: Discussionmentioning

confidence: 99%

A three-year mark-recapture study in a remnant population of Crocodylus acutus Cuvier in Portete Bay (Guajira, Colombia)

Espinosa

Bertin

Gómez³

et al. 2012

Gayana (Concepc.)

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RESUMENEl Cocodrilo Americano Crocodylus acutus, ha experimentado importantes declines poblacionales a lo amplio de su distribución debido a la persecución humana, la sobreexplotación y la pérdida de hábitat. C. acutus permanece en peligro crítico en algunos países tales como Colombia donde la ausencia de estudios detallados sobre su ecología y distribución constituyen una de las barreras principales para el desarrollo de efectivas estrategias de conservación. Durante tres años desarrollamos un estudio de captura-recaptura para investigar el estatus demográfi co de C. acutus e identifi car las variables medioambientales más infl uyentes en su distribución en Bahía Portete (Colombia). Nosotros estimamos que la población de cocodrilos es relativamente pequeña (< 140 animales), incluye muy pocos adultos y demuestra un fuerte défi cit de hembras en la clase juvenil. La humedad relativa y la temperatura promedio del aire estuvieron positivamente correlacionadas con el número de avistamientos de cocodrilos. Por el contrario, la salinidad promedio del agua se encontró relacionada con la baja probabilidad de observación, presumiblemente debido a la preferencia de los juveniles por áreas de baja salinidad. Nuestros resultados sugieren que la población de C. acutus en Bahía Portete está en riesgo y puede requerir la intervención humana para asegurar su persistencia.Palabras claves: Captura-recaptura, cocodrilo, variables medioambientales, manglar ABSTRACTThe American crocodile, Crocodylus acutus, has experienced important population declines worldwide due to human persecution, overexploitation and habitat loss. C. acutus remains critically endangered in some countries such as Colombia where the lack of detailed surveys on its ecology and distribution constitutes a major barrier to the development of effective conservation strategies. We conducted a three-year capture-recapture study to investigate the demographic status of C. acutus and to identify environmental variables likely to infl uence its distribution in Portete Bay (Colombia). We estimated the crocodile population to be relatively small (< 140 animals), to include very few adults, and to demonstrate a very strong defi cit in females in the juvenile class. Both mean air temperature and relative humidity were positively correlated with the number of sightings. In contrast, mean water salinity was found to decrease the probability of observing a crocodile, presumably due to juvenile preference for low salinity areas. Our fi ndings suggest that the population of C. acutus in Portete Bay is at risk and may require human intervention to assure its persistence.

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“…Miniature temperature dataloggers have become valuable tools for the study of thermal ecology in a diversity of ectotherms and heterothermic endotherms, including mammals (Warnecke et al, 2007), birds (Laurila and Hohtola, 2005), reptiles (Downs et al, 2008), amphibians (Rowley and Alford, 2010), fishes (Donaldson et al, 2009), and invertebrates (Jones et al, 2004). They have been used to record body temperatures of animals of all sizes, ranging from elephants (Kinahan et al, 2007) to elephant shrews (Mzilikazi et al, 2002), through surgical implantation (Taylor et al, 2004), insertion into the gastrointestinal tract (Kinahan et al, 2007) or ear canal (Munn et al, 2009), or attachment to the animal's outer surface (Grayson and Dorcas, 2004).…”

Section: Introductionmentioning

confidence: 99%

“…Even if it is possible to replace failed devices, the lost data may not be replaceable. As an alternative solution, many researchers have waterproofed iButtons by sealing them with materials such as plastic tool dip (designed to coat tool handles; e.g., Grayson and Dorcas, 2004;Taylor et al, 2004;Donaldson et al, 2009), surgical wax (e.g., Downs et al, 2008;Bieber and Ruf, 2009;Gür et al, 2009), parafilm (Schwanz et al, 2010), silicone sealant (Lautz et al, 2010), and balloons (Lutterschmidt et al, 2006;Kearney et al, 2011).…”

Section: Introductionmentioning

confidence: 99%