Mark posted this in a discussion with Rsg.
mark wrote,
Posted by: mequinn at Fri Aug 20 22:34:51 2004 [ Report Abuse ] [ Email Message ]
Terrestrial-based Australian varanids go through a climatic dry and wet period, as you probably know. In 'wild' During the dry season, the terrestrial Varanids (i.e. V. gouldii, V. acanthurus) have a drop in body weight, and a gain of body weight in the wet season; the reverse is known for V. mertensi as it drops body weight in the dry season and gains body weight in the wet season, as V. mertensi does not brumate/hibernate/ dormancy and is active year-round. Its water -uptake is significantly higher than its terrestrial counterparts in both the wet and dry seasons (Christian, 1996. Energetics and water flux in a semiaquatic lizard Varanus mertensi. Copeia (2):354-362) - does this not 'suggest' they require more water than a terrestrial species, and when available will hydrate themselves whenever possible, i.e. bathing/soaking?? It does to me....
So where did I miss your point? You say V. mertensi "prefer" swimming/in the wet than do V. acanthurus - does'nt that mean they require it?? Preference is a choice issue, and V. mertensi do not go swimming for 'fun'? They do this to thermoregulate, hydrate, and stablelize metabolic processes with the addition/deletion of water, which is crucial to their metabolic functions. Some varanids require more water than others, have lower optimal body temps than others (i.e. V. salvator's 85F), hence its constant use or "preference" for soaking/swimming = it does this because it has too, and not for mere enjoyment/pleasure. Varanids are reptiles, and reptiles I do not think they have 'joy'(pleasure, ectasy etc..) in their innate or learned behavior categories. They "prefer" to soak because they have to to sustain their metabolic functions for an animal where they are in the water more than a V. acanthurus. V. acanthurus have adapted through time and genetics to maintain a higher water content in their physiology than V. mertensi, hence they retain their water more efficiently, vrs. V. mertensi which does not but is always associated with water, in water, around water a majority of the time on an annual basis....one does not have to keep varanids to understand this...this is where knowledge of an animal can be important to a herp keeper to know something about the animals in their keep to know which ones 'prefer' aquatic, semi-aquatic, terrestrial, arboreal, habitats and adjust their terraria to them....and where many animals die as they do not understand or grasp this primary requirement to successful husbandry (not necessarily to you, but others reading this)...
mbayless
While this sounds great, I have several questions.
Have you been to australia and seen these monitors doing this stuff? put answer here.
Do you understand, that ackies occurr from the very top of oz, 7 degrees off the equator, to south of the tropic line. They occur in deserts without a rainy season, that freezes. They occur all the way to the very top in habitats that are tropical to semi tropical and have a wet and dry season. They also occur in the pilbara, that has no distint rainy season,(overflow from both north and south), thats very hot and arid. So your comparison is very weak, as V.mertensi, only occurs in the topend and avoids freezing weather(only lite freezes) V.mertensi, commonly estavates in the dry season, as the billibogs dry up, as most do. In very dry years, they may spend the better part of a year underground. Mertens in the Mt. Isa area to the Halls Creek area, can and do experience prolonged dry periods with absolutely no water.
Before you make your comments, you should research more. or at least go visit. Thanks FR
