Frogs and toads

Toads that were not olfactorily impaired and those that were blinded, showed a clear ability to relocate their capture site. Anosmic toads appeared to be disoriented. The authors concluded that olfactory cues provided the principal means of orientation in these animals. However, the authors also pointed out that changes in variables such as cloud cover, celestial cues, and wind direction could have influenced these results. Moreover, they suggested that severing the olfactory nerve could have eliminated the desire to return to the breeding site rather than their ability to relocate it.  

Dole (1965, 1968) studied homing and orientation in leopard frogs Rana pipiens) under a variety of conditions using methods similar to those described above. As in B. boreaSy blinded R. pipiens could home as successfully as normal individuals displaced comparable distances, from both upwind and downwind of home. 

Grubb (1970) examined homing ability and orientation in individually marked postreproductive Mexican toads (Bufo valliceps). Displacements were conducted by transporting toads in light-proof bags various distances from their capture 

All intact toads were recaptured within ten days after displacement. Twenty of 23 blinded toads moved toward home. Ten toads that received formalin injections also moved toward home. In 9 of 14 trials, toads with destroyed olfactory tracts also moved toward home. Control toads given the same operation procedures but not made anosmic also moved toward home. Only three of 24 toads that were both blind and anosmic moved toward home. Grubb concluded that both visual and olfactory cues are used in homing in Mexican toads. 

Animals were tested by placing them under an inverted wire mesh basket upwind from the fan and released when the basket was raised by a pulley. Groups of animals were tested. Group size varied with the species being tested. Different species were tested for different durations. For example, some species were tested for 10 min, whereas several tree frog species (e.g., Hyla chrysoscelis and Pseudacris clarki) were tested for at least 20 min. The testing times were arbitrarily set but were consistent within species. 

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D-Galactose H HO HO H HOH2 C—C—C—C—C—CHO HO H H HO widespread in plants lactose ovomucoid cerebrosides albumin gland of snail frog and toad spawn beef lung... 

Frogs and toads Yugoslavia liver near mercury mines ... 

Meteyer, C.U. 2000, Field Guide to Malformations of Frogs and Toads with Radiographic Interpretations. USGS National Wildlife Health Center, Madison, WI Biological Science Report No. USGS/BRD/BSR-2000-0005. 

Aquatic frogs and toads probably need less toxin for defense than terrestrial forms. The compounds in the frogs mucus are thought to be neuroleptic, blocking dopamine receptors. They also possibly are antibacterial and aid wound repair, and they are known to elevate the level of prolactin, the amphibian Juvenile hormone (Barthalmus and Zielinski, 1988). 

Flier, J. M., Edwards, W., Daly, J. W., and Meyers, C. (1980). Widespread occurrence in frogs and toads of skin compounds interacting with the ovabain site of Na+, K+-ATPase. Science 208,503-505. 

There are three orders within the class Amphibia. Order Anura is the largest of these, with over 5000 living species. This group includes frogs and toads. The order Urodela includes the 510 species of salamanders and their relatives. The smallest group is order Apoda, the caecilians, which are legless, blind, wormlike animals that borrow in the soil. 

Moore, J. A. 1955. Abnormal combinations of nuclear and cytoplasmic systems in frogs and toads. Advances in Genetics, 7, 132-182. 

Many frogs and toads contain high levels of N- and 0-methylated amines derived from the indolic biogenic amines serotonin and tryptamine, as well as other amines, such as the tyramines and catecholamines. Such simple... 

Whether Shakespeare knew of the toxins in some frogs and toads is doubtful. We don t normally associate frogs and toads with poison because they don t bite. However, some frogs and toads, for example the frog dendrobates, produce very potent toxins to ward off or even kill... 

Toads can also produce toxins, which are different from those produced by frogs, one of which, bufotenin, has similar effects to LSD, causing hallucinations and also lowering blood pressure. Another toxin, bufotahn, affects heart function like digitalis, which may lead to arrythmias and death. Cases of poisoning have occurred as a result of people handling these frogs and toads, as some of them can produce considerable amounts of the toxins. 

Choice of Pond Odors by Newts, Frogs, and Toads... 

The criticism often presented about the FETAX is that it is a poor representation of native species of amphibians or of other vertebrates. Xenopus is of course not native to the Americas, but it is a typical amphibian and its comparability in teratogenic response to mammalian species has already been documented. Xenopus is also widely available, and the basic methodology can also be transferred to other frogs and toads. 

The lymphoid system of the amphibians is more complex than that of fishes. In addition to a well-defined thymus gland, primitive lymph node tissue is also present (Kent et al., 1964). In frogs and toads for the first time marked seasonal changes in thymic size are noted (Dustin, 1911). Reptiles have a lymphoid system that is quite similar to that seen in amphibians, including a well-developed thymus that also involutes with age (Dustin, 1911). 

Deoxy-5a-cyprinol 5a-Cholestane-3o,7a,12a,26-tetrol Some fishes some frogs and toads... 

Deoxy-5/8-cyprinol 5/8-Cholestane-3o,7a, 12 a,26-tetrol Some frogs and toads... 

Ground cover Many creatures, such as ground beetles and centipedes, need the dark, moist conditions that exist underneath groundcover plants or plant material to survive. Frogs and toads can find shelter under low-growing plants, too. 

Such comparisons have also been made using the minimum systole arrest dose in frogs following injection into the anterior lymph sac but the values obtained may be of little validity. There appears to be marked differences in summer and winter frogs (107), wide variations in intensity of response to different animal species (108), and considerably different sensitivities between the frog and toad (109). Santi (110) has compared the minimum fatal dose (systolic arrest) in frogs (Rana esculenta). The various alkaloids, as hydrochloride or sulfate salts, were injected into the... 

Elevated concentrations of mercury in amphibian tissues were also found in frogs and toads collected near a mining area in Yugoslavia. Maximum concentrations, in mg/kg fresh weight, were 2.3 in egg, 2.9 in lung, 24.0 in kidney, and 25.5 in liver conspecifics from a reference site contained <0.08 mg Hg/kg fresh weight in all tissues. 

Pumdiotoxins (PTX). Alkaloids isolated from the arrow poison frog Dendrobates pumilio with indolizi-dine (P. A and B) or decahydroquinoline skeletons (P. C). The P. were later also detected in other frogs and toads. ... 

Bloom, G. 1954. Studies on the olfactory epithelium of the frog and toad with the aid of light and electron microscopy. Z. Zellforsch. mikrosk. Anat. 41, 89—100. 

Among vertebrates, mechanisms underlying kin recognition abilities of anuran amphibians (frogs and toads) have been perhaps most extensively studied. Anuran larvae can be easily manipulated for developmental or sensory experiments. Their recognition abilities are thus much more amenable to analysis than are those of birds or mammals. In addition, they can be obtained and reared in large numbers and show easily measurable kin association responses in a variety of laboratory and field testing situations. 

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