Instead, they use strong pheromones. Almost all snakes can make a hissing noise by forcing air out of their glottis the end of the trachea. Snakes have inner ears and can hear certain noises, but they specialize in picking up ground-borne vibrations. This enables them to identify when potential predators are approaching. Snakes are adapted to hear only low-pitched sounds. Most snakes hear sounds in the range of 80 to Hz most clearly, although some species can hear sounds up to 1, Hz. Pheromones are chemicals secreted through the skin.
Snakes deposit them on the ground, although some have also been found to be airborne, according to research published in Biology Letters. The pheromones are species-specific.
The chemical makeup of the pheromones changes as the snake ages, and becomes sexually mature. When a snake detects pheromones from another snake, it will instantly know if the other snake is male or female, and whether it is ready to mate. However, snakes are known to exhibit some kind of communication with one another. Majority of communication method of snakes are made for finding, defending and securing their breeding partners.
You will learn how snakes do communicate through the content of this post. Snakes Communicate Using the Vemeronasal System Snakes are equipped to interactive and analyze chemical cues around them through their sense of taste, smell as well as through vemeronasal system.
As they face a variety of threats stemming from human activities, these snakes are vulnerable to extinction. Common Name: King cobras. Scientific Name: Ophiophagus hannah. Type: Reptiles. Diet: Carnivore. Group Name: Quiver. Size: 13 feet. Weight: Up to 20 pounds. Size relative to a 6-ft man:. Least Concern Extinct. Current Population Trend: Decreasing. This photo was submitted to Your Shot, our photo community on Instagram. Follow us on Instagram at natgeoyourshot or visit us at natgeo.
Share Tweet Email. Go Further. Animals Wild Cities This wild African cat has adapted to life in a big city. Nocturnal or crepuscular species, such as the cat-eyed snakes Leptodeira , frequently have distinctively developed eyes with vertically elliptical pupils. Many of the predominantly subterranean forms, such as the blind snakes Leptotyphlops , have small or vestigial eyes. Snakes are capable of hearing, but only over certain frequency bands, and in general do not appear to depend on hearing Wever and Vernon, They are, in addition, sensitive to low-frequency ground vibrations.
On the basis of anatomical features the senses of taste and smell appear well developed and include such specialized organs as that of Jacobson Bellairs, The constant use of the tongue in many species of snakes, of course, is well known. Bogert demonstrated experimentally that rattlesnakes Crotalus could recognize king snakes Lampropeltis , which prey on them, by odors given off by the kingsnakes.
Gehlbach, Watkins, and Kroll have shown that several species of snakes are capable of following pheromone trails. For example, blind snakes Leptotyphlops dulcis are able to follow the pheromone trails laid down by army ants Neivamyrmex nigrescens , on which they prey. The pits of the pit vipers form a special sense organ used for the detection of infrared radiation and the tracking of warm-blooded prey.
But there is no indication that this modality is used in communication. The daily activity patterns of different species of snakes are as variable as those of lizards. Snakes appear to tolerate a greater range of environmental temperatures in their activity than do lizards.
Annual activity patterns are generally poorly known. Some species of temperate zone snakes aggregate at "dens" for hibernation, and mating may take place near these dens Evans, Information on the reproductive cycles of snakes has been summarized by Fitch The visual appearance of snakes is as varied as their habits and habitats see Schmidt and Inger, ; Mertens, , ranging from cryptic to aposematic. Many species of snakes can inflate themselves or flatten the neck region.
Sometimes this action causes the appearance of a particular pattern, as in the cobras and the African bird snake Theletornis: Blair, In general, modifiable appearance mechanisms are not as well developed or common as in lizards. Vocalizations are restricted to hissing, which does not appear to serve a communicatory function. Other sounds produced by snakes, such as the rattle of the rattlesnake, also appear not to function in communication Gans and Mader son, Snakes produce a variety of smells and secretions, many of which are powerful and disagreeable to human beings and serve a defensive function Mertens, The best-known case of chemical communication in snakes is that of the blind snake Leptotyphlops dulcis, studied by Watkins, Gehlbach, and Kroll These workers have demonstrated that blind snakes show a complex set of behavioral responses to their cloacal sac secretions.
They are attracted to the secretion, which may cue both food sources and potential mates. On the other hand, several genera of snakes, which are sympatric with blind snakes Sonora, Tantilla, Virginia, Diadophis, and Lampropeltis and which include both potential competitors with and predators of blind snakes, are repelled by the secretion.
In addition, army ants Neivamyrmex nigrescens, on which the blind snakes prey, as well as other species of ants are repelled by the secretion. The secretion itself is a mucuslike glycoprotein suspended in free fatty acids Blum et al. It is quite likely that these studies represent only the tiniest tip of the iceberg of chemical communication in snakes. The meager information available on social systems and intraspecific interactions and communication is summarized by Evans and Brattstrom One of the few obvious intraspecific interactions of snakes is the male combat dance, which usually takes the form of a ritualistic pushing match between males, although entwining may occur in some cases.
Bogert and Roth list twenty six species in four families Colubridae, Elapidae, Viperidae, and Crotalidae for which male combat has been reported. They also give a detailed description of the combat of male gopher snakes Pituophis melanoleucus.
Several interpretations have been given to this behavior by various authors, including the idea that these combats represent attempts at homosexual matings. These interpretations have been reviewed by Brattstrom , who concludes that more information is needed before the problem can be solved.
Lowe and Norris review the known cases in which aggressive behavior in snakes is known to be associated with defense of a particular area, most notably in the cobras and their allies Elapidae. They conclude that one of the functions of aggressive behavior in snakes may be the maintenance of territories.
However, they too caution that insufficient information is available to determine the function or functions of aggressive behavior in snakes. Clearly, the relationships of aggressive behavior and movement and spacing patterns represent an outstanding problem in snake biology. Virtually all turtles possess well-developed eyes and visual acuity.
Hearing in turtles has been found to be fairly good in some species Wever and Vernon, Many species of chelids possess large inner-ear structures, which may indicate the importance of hearing.
As with snakes, turtles appear sensitive to low-frequency ground-transmitted vibrations. Olfaction also seems important in turtles. Eglis has described the motor patterns associated with sniffing behavior in several species of tortoise. This behavior may be quite stereotyped and is associated with the habit of sniffing at many objects in the environment.
Some species, such as mud turtles Kinosternon and their relations and many side-necked turtles Chelidae and Pelomedusidae , possess barbels—papillae on the chin or throat—which may serve a chemore ceptive function. Most turtles' shells are basically cryptic in appearance. Even the brightly colored black and yellow shells of species like the star tortoise of India Geochelone elegans are cryptic in the habitats in which they live.
On the other hand, the head and limbs of many species are quite distinctively and obviously colored. Thus turtles have the opportunity of controlling their appearance by withdrawing into or coming out of their shells.
In addition, many possess stereotyped movement patterns consisting of head-nods and particular movements of the forelimbs, which are used in communicatory situations such as courtship and agonistic behavior.
The iris of the eyes of male box turtles Terrapene Carolina develops a bright red color during the breeding season. Evans , found that this coloration is controlled by the hormone testosterone and functions as a releaser in courtship. Many turtles can produce vocalizations of some sort, and these cases have been reviewed by Gans and Maderson Social vocalizations have been found in groups of aggregated Geochelone travan corica, a tortoise of India Campbell and Evans, , in situations other than courtship.
But the biological function of the sounds remains unknown. Several turtles produce distinctive odors and have special glands to do so. The best known examples are the musk turtles or stinkpots Sternotherus: Carr, But whether these odors are used other than in defense is unknown.
Most turtles are diurnal, and many water turtles commonly aggregate to bask. Annual cycles of movement are poorly known except in the sea turtles, such as the green turtle Chelonia my das and the ridley Lepidochelys kempi , which migrate to particular beaches and form great aggregations for breeding Carr, , Many species of water turtles show seasonal movements overland Gibbons, , but the reasons for these movements are not well known.
Courtship behavior in turtles has been described for several species Ernst and Barbour, More detailed studies of several species of tortoise Gopherus and Geochelone have been provided by Auffenberg , , and of members of the freshwater genus Pseudemys by Davis and Jackson , and Jackson and Davis In most cases the male display consists of patterns of head movement "nods" and attempts to bite or bump the female. Male water turtles also use the feet and claws to stimulate the female. Auffenberg suggests that glands on the chin of male Gopherus may produce a pheromone involved in courtship.
Auffenberg found that individuals of two sympatric South American tortoises Geochelone carbonaria and G. Male tortoises, such as the Galapagos tortoise Geochelone elephantopus sometimes vocalize "roar" while mating Campbell and Evans, ; Gans and Maderson, Otherwise, few studies of species recognition for mating have been carried out on turtles. Some male sea turtles are notoriously nondiscriminatory during the breeding season.
Male green turtles Chelonia mydas will often attempt to mate with almost any object of the appropriate size, including wooden decoys placed by fishermen Carr, Social organization and spacing mechanisms are not obviously well developed in turtles or tortoises. It is sometimes claimed that turtles possess no social spacing mechanisms, a characteristic Legier attributes to ornate box turtles Terrapene ornata on the basis of field observations.
Yet in a laboratory situation under conditions of artificial crowding Harless and Lambiotte found evidence for a social hierarchy in this species. Hierarchical behavior has also been reported for captive eastern box turtles TerrapeneCarolina: Boice, , and Galapagos tortoises Geochelone elephantopus: Evans and Quaranta, Combat between males in the field has been reported for the Texas tortoise Gopherus berlandieri: Weaver, and desert tortoise Gopherus agassizi: Patterson, In addition, Patterson found evidence for genuine territoriality in the desert tortoise, which marks out territories with the use of urine and feces.
The biology of crocodilians has been reviewed by Neill and Guggisberg , but only little progress has been made in recent years in understanding communication among these animals. These rather generalized reptiles possess the usual range of vertebrate sensory modalities. They do not seem to have any ability to change their appearance. Males of many species, including the American alligator Alligator mississipiensis , produce striking vocalizations "bellows" and "roars" , which appear to be used in part as spacing mechanisms Beach, ; Campbell, Lee advances the hypothesis that the noises made by unhatched alligators serve a communicatory purpose.
In some preliminary experiments he found that individual eggs within an artificially composed clutch would hatch out synchronously, although the eggs came from different clutches laid at different times. He suggests that the noises and possibly the movements made by the unhatched alligators may be the mechanisms by which synchronization is achieved, and that synchronous hatching helps to avoid predators. This line of investigation bears following up. Crocodilians of both sexes also produce strong distinctive odors by means of special musk glands.
The existence of maternal behavior in alligators has been the subject of some debate Neill, Kushlan reports a case of a female American alligator's retrieving young and suggests that maternal behavior definitely exists in this species.
Female alligators are also reported to guard their nests and to uncover the eggs at the time of hatching. Although there is good evidence that some kind of maternal behavior does occur in this species, the mechanisms by which the mothers recognize the young and the role of communication between mother and young remain unknown. Two points seem to stand out. First, I would agree with and generalize from Brattstrom's remarks that "there is more to snake social behavior than has been assumed.
Even in iguanid lizards, whose social and communication systems are probably better known than those of any other amphibians and reptiles, there are still questions about the existence of social organization in some genera. For example, Lynn reported that territoriality did not exist in horned lizards Phrynosoma and that displays were "weak" by iguanid standards. On the other hand, Whitford and Whitford report on actual combat in horned lizards. If combat is at all frequent, it is difficult to imagine that some sort of organization does not exist among populations of these lizards.
In general, most amphibians and reptiles have been so poorly studied that the extent of social and communication behavior is in most species only dimly appreciated. Leyhausen has emphasized that many solitary species of mammals whose members encounter each other only infrequently have, nonetheless, rather complex social organizations. Thus communication between members of these species, no matter how fleeting or subtle, may have significant social and hence ecological consequences.
I would expect that similar considerations may apply to many amphibians and reptiles. Second, I would agree with and generalize from the remarks of Gans and Maderson , who conclude that the "sound-producing mechanisms [of reptiles] here described represent a random assemblage, with no central evolutionary tendency. Stated more precisely, there is no clear phylogenetic model of communication behavior in these groups, partly because they do not constitute a natural phylogenetic assemblage herpetology as a discipline thus sometimes seems to be a bit ill conceived.
In addition, both groups have undergone extensive ecological and adaptive radiation. The attempt to analyze communication behavior in amphibians and reptiles from an ecological point of view has not made great progress, because of the reasons discussed above.
However, such an attempt does emphasize a class of questions and problems to which future research may profitably be devoted. I suggest that communication behavior should be studied in connection with the entire life history and life-history strategy of the species in question. Below are a number of areas of interest in the communication biology of amphibians and reptiles that are best studied in this fashion.
A central problem in the communication behavior of amphibians and reptiles is that in many cases no immediate response is evidenced on the part of the supposed recipient, or there may be no obvious recipient at all.
Frogs, geckos, and alligators all call, lizards give signature bobs, and so forth, without necessarily provoking any immediate response in a particular conspecific. However, there are examples of long-term responses to short-term communicatory acts: female Anolis carolinensis are induced to undergo ovarian recrudescence, in part, by viewing communicatory behavior by the male.
I would expect that a similar phenomenon may occur as a result of calling by some species of frogs; that is, frog calls may affect hormonal and reproductive cycles in some species.
If this hypothesis is true, it would help to explain the existence of some frog calls that are not given at the exact time or site of breeding Bogert, Further, it would provide a mechanism for the synchronization of breeding cycles.
Cunningham and Mullally have hypothesized that male Pacific tree frogs Hyla regilla are synchronized and that calls are, in part, responsible. These ideas need to be tested experimentally, and hypotheses of long-term response to communication need more attention generally. Also, one can easily imagine that many territorial signals are given on the statistical expectation that a conspecific may be nearby and will perceive it.
It may well be the case that much of the communication behavior of amphibians and reptiles may be of this statistical nature and not necessarily adapted only for direct, one-to-one encounters with individuals of their own species. If so, then the communication behavior can be understood only in the context of the statistical structure of the environment, in particular, in the context of the statistical expectation of the presence of conspecifics and their expected correlation with the resources in the environment.
Unless communication behavior of amphibians and reptiles is studied in its ecological context, any attempt to compare displays between species or to compile a complete catalog of displays may lead to error.
For example, there is some confusion in the literature in listing different types of calls emitted by frogs. Whether a certain species of frog possesses a call type previously described for another species or whether a given call is a mating call, a variation on the mating call, a territorial call, or a rain call can only be determined by studying the use of the call in the life history of the frog.
Further, as Atz has emphasized, the homologies of behavior are difficult to determine, and comparisons of displays and their ecological contexts may help us understand the extent of this problem. Finally, only if the catalogs of the displays of any one species are compiled in reference to a complete knowledge of the life history of the species can the catalog be complete. It is only when complete catalogs are available that such information can be used to attack problems such as those posed by Moynihan's analysis of the evolution of display repertoires.
Such a study of communication in an ecological context could also reveal the effects of environmental variation. Temperature variation is undoubtedly the best example of such effects. It is well known that temperature affects both sensory and species-perceptibility mechanisms. Even the frequency of the rattlesnake's rattle is temperature-dependent Martin and Bagby, To understand these effects, both the temperature dependence of the physiological systems and the distribution of temperatures normally encountered in the environment must be determined.
In addition, there is evidence that temperature variation affects more general behavior, such as learning ability Krekorian, Vance, and Richardson, It is possible that other physical factors may affect communication systems as well. The study of the mechanisms of species recognition has been a goal of many analyses of communication behavior in amphibians and reptiles.
This has been true of studies of both frog calls and lizard display action patterns. However, it seems that species recognition is a complex of phenomena rather than single phenomenon for each species. The functions of species recognition are to find mates, select mates, synchronize breeding cycles, estimate patterns of environmental variability, and structure daily movement patterns Kiester and Slatkin, , select habitats Kiester, ms.
Connected with the multiplicity of functions of species recognition is the fact, emphasized to me by Stanley Rand, that species recognition does not work with the same precision at all times. For instance, an individual may sometimes react to a member of another species as if it were a conspecific.
Thus we may expect that the precision may vary from species to species and depend on both the ecological context and the strategic use to which the information gained by recognition is put. The ecological context includes the other species in the environment that may be confused with conspecifics or whose presence may sometimes impart the same information as a conspecific. The strategic considerations may include the degree to which conspecifics influence such activities as daily movement patterns and habitat selection.
Although no unequivocal evidence exists to show that individual recognition does occur in amphibians or reptiles, it is a possibility. Evans reported that subordinant individuals in a hierarchy of Mexican black iguanas Ctenosaura pectinata would react in a characteristic fashion to the approach of the dominant "tyrant" male. It is possible that they were responding simply to his size rather than to him per se. However, if individual recognition does occur, many of the complexities described for species recognition will have to be investigated.
Adler, K. The role of extraoptic photoreceptors in amphibian rhythms and orientation: a review. Herpetology, Arnold, S. The Evolution of Courtship Behavior in Salamanders. Atz, J. The application of the idea of homology to behavior. In: Development and Evolution of Behavior, L. Aronson et al.
New York: W. Freeman 8c Co. Auffenberg, W. Notes on the courtship of the land tortoise Geochelone travaneorica Boulenger. Bombay Natur. Sex and species discrimination in two sympatric South American tortoises. Copeia, On the courtship of Gopherus polyphemus. Herpetologica, Beach, F. Responses of captive alligators to auditory stimulation. Bellairs, A. The Life of Reptiles, 2 vols.
New York: Universe Books. Benes, E. Behavioral evidence for color discrimination by the whiptail lizard, Cnemidophorus tigris. Berry, K. The ecology and social behavior of the chuckwalla. Blair, A. Isolating mechanisms in tree frogs. Isolating mechanisms in a complex of four species of toads. Symposia, Blair, W. Call difference as an isolation mechanism in southwestern toads Genus Bufo. Texas J. Mating call in the speciation of anuran amphibians.
Austin: University of Texas Press. Isolating mechanisms and interspecies interactions in anuran amphibians. Amphibians and reptiles. In: Animal Communication, T. Sebeok, ed. Bloomington: Indiana University Press, pp. Character displacement in frogs. Blum, M. II; and Gehlbach, F. Chemistry of the cloacal sac secretion of the blind snake Leptotyphlops dulcis.
Bogert, C. Sensory cues used by rattlesnakes in their recognition of ophidian enemies. The influence of sound on the behavior of amphibians and reptiles. In: Animal Sounds and Communication, W. Lanyon and W. Tavolga, eds.
Ritualistic combat of male gopher snakes, Pituophis melanoleucus affinis Reptilia, Colubridae. Boice, R. Competitive feeding behaviors in captive Terrapene c. Animal Behaviour, Competitive feeding behavior of Rana pipiens and Rana clamitans. Hierarchical feeding behavior in the leopard frog Ranapipiens. Brattstrom, B. Call order and social behavior in the foam-building frog, Engystomops pustulosus. The evolution of reptilian social behavior.
Brown, C. Additional observations on the function of the nasolabial grooves of Plethodontid salamanders. Brown, L. Male release call in the Bufo americanus group. In: Evolution in the Genus Bufo, W. Blair, ed. Austin: University of Texas Press, pp. Bunnell, P. Vocalizations in the territorial behavior of the frog Dendrobates pumilio. Burrage, B. Comparative ecology and behaviour of Chamaeleo pumilus pumilus Gmelin and C. Smith Sauria: Chamaeleonidae. African Mus. Campbell, H. The effects of temperature on the auditory sensitivity of lizards.
Observations on the acoustic behavior of crocodilians. Zoologica New York , Sound production in two species of tortoises. Observations on the vocal behavior of chelonians. Capranica, R. The Evoked Vocal Response of the Bullfrog.
Monograph Cambridge: M.
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