Freshwater Turtles
Turtles are diapsids of the order Testudines (or Chelonii) seen as a a special bony or cartilaginous shell created from their ribs plus acting as a protect. "Turtle" may refer to the order as the whole (American English) or to fresh-water and sea-dwelling testudines (British English). The particular order Testudines includes each extant (living) and vanished species. The earliest known members of this group date from 220 million years ago, making turtles one of the oldest reptile groups and a more ancient group compared to snakes or crocodilians. Of the 356 known species alive today, some are highly endangered.
Turtles are ectotherms—animals commonly called cold-blooded—meaning that their internal temperature varies according to the particular ambient environment. However, because of their high metabolic rate, leatherback sea turtles have a body heat that is noticeably increased than that of the particular surrounding water. Turtles are usually classified as amniotes, together with other reptiles, wild birds, and mammals. Like additional amniotes, turtles breathe air and do not place eggs underwater, although numerous species live in or even around water. The study of turtles is known as cheloniology, following the Greek phrase for turtle. It is also sometimes called testudinology, after the Latin title for turtles.
Differences exist in usage of the particular common terms turtle, tortoise, and terrapin, based on the range of English being used. These terms are common names and don't reflect exact biological or taxonomic distinctions.
Turtle may either relate to the order since a whole, or to particular turtles that create up a form taxon that is not monophyletic, or may be limited to only aquatic species. Tortoise usually refers to any land-dwelling, non-swimming chelonian. Terrapin is used in order to describe several species of small, edible, hard-shell turtles, typically those found in brackish waters.
In Northern America, all chelonians are commonly called turtles. Tortoise is used only within mention of the fully terrestrial turtles or, more narrowly, just those members of Testudinidae, the family of modern property tortoises. Terrapin may relate to small semi-aquatic turtles that live in new and brackish water, specifically the diamondback terrapin (Malaclemys terrapin). Although the people from the genus Terrapene dwell mostly on land, they are referred to as box turtles rather than tortoises. The particular American Society of Ichthyologists and Herpetologists uses "turtle" to describe all species of the order Testudines, regardless of whether they are land-dwelling or sea-dwelling, and uses "tortoise" as a more specific term for slow-moving terrestrial species.
In the United Kingdom, the term turtle is used for water-dwelling species, including ones known in the particular US as terrapins, although not for terrestrial species, that are known only as tortoises.
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Marine turtles characteristics, key to the 7 marine species, ecology, habitat and range, behavior
The word chelonian will be popular among veterinarians, scientists, plus conservationists working with these animals being a catch-all name for any member of the particular superorder Chelonia, which includes all turtles living and extinct, as well as their own immediate ancestors. Chelonia is usually based on the Ancient greek word for turtles, χελώνη chelone; Greek χέλυς chelys "tortoise" is also used in the formation of scientific names of chelonians. Testudines, on the other hand, is based on the Latin word for tortoise, testudo. Terrapin comes through an Algonquian word regarding turtle.
Some languages do not have this distinction, as all of these types of are referred to by the same name. For instance , in Spanish, the word tortuga is used for turtles, tortoises, and terrapins. The sea-dwelling turtle is tortuga marina, a freshwater types tortuga de río, and a tortoise tortuga terrestre.
The largest living chelonian is the leatherback sea turtle (Dermochelys coriacea), which usually reaches a shell length of 200 cm (6. six ft) and can achieve a weight of over 900 kg (2, 000 lb). Freshwater turtles are generally smaller, but along with the largest species, the Asian softshell turtle Pelochelys cantorii, a few individuals have been reported upward to 200 cm (6. 6 ft). This dwarfs even the better-known alligator snapping turtle, the biggest chelonian in North America, which attains a shell length of up to 80 cm (2. six ft) and weighs as much as 113. four kg (250 lb).
Giant tortoises of the genera Geochelone, Meiolania, and other people were relatively widely dispersed around the world into prehistoric times, and are known to have got existed in North and South America, Australia, and Africa. They became extinct at the same period as the appearance associated with man, and it will be assumed humans hunted them for food. The only surviving giant tortoises are usually on the Seychelles and Galápagos Islands and can grow to over 130 cm (51 in) in size, and weigh about 300 kg (660 lb).
The largest ever chelonian had been Archelon ischyros, a Late Cretaceous sea turtle known to have been as much as 4. 6 m (15 ft) long.
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The smallest turtle is the speckled padloper tortoise of Southern Africa. It measures simply no more than 8 cm (3. 1 in) in length and weighs about 140 g (4. 9 oz). Two other species associated with small turtles are the American mud turtles and musk turtles that live in an area that ranges from Canada in order to South America. The covering length of many species within this group is much less than 13 cm (5. 1 in) long.
Turtles are divided into two groups, according to how they retract their necks to their shells (something the ancestral Proganochelys could not do). The mechanism of neck retraction differs phylogenetically: the suborder Pleurodira retracts laterally aside, anterior to shoulder girdles, while the suborder Cryptodira retracts straight back, between shoulder girdles. These motions are largely due to the morphology and arrangement of cervical backbone. Of all recent turtles, the cervical column consists of nine joints plus eight vertebrae, which are usually individually independent. Since these types of vertebrae are not fused and are rounded, the neck is more flexible, being able to flex in the backwards and sideways directions. The major function and evolutionary inference of neck retraction will be thought to be for feeding rather than protection. Neck retraction and testing extension allows the turtle to achieve out further in order to capture prey while swimming. Neck expansion creates suction when the head is thrust forward and the oropharynx is expanded, and this particular morphology suggests the retraction function is for nourishing purposes as the suction helps catch prey. The protection the shell provides the head when this is retracted is therefore not the main function of retraction, thus is usually an exaptation. As for the difference between the particular two methods of retraction, both Pleurodirans and Cryptodirans use the quick expansion of the neck like a method of predation, therefore the difference in retraction mechanism is not really due to a difference in ecological niche.
Head
Most turtles that spend most of their lives on property have their eyes looking down at objects in front side of them. Some marine turtles, such as nipping turtles and soft-shelled turtles, have eyes closer to the very best of the head. These species of turtle may hide from predators in shallow water, where they will lie entirely submerged other than for their eyes and nostrils. Near their eye, sea turtles possess glands that produce salty tears that rid themselves associated with excess salt taken in through the water they consume.
Turtles have rigid beaks and use their jaws to cut and chew food. Instead of having teeth, that they appear in order to have lost about 150-200 million years ago, the particular upper and lower teeth of the turtle are usually covered by horny side rails. Carnivorous turtles usually have knife-sharp ridges for cutting through their prey. Herbivorous turtles have serrated-edged side rails that help them reduce through tough plants. They use their tongues in order to swallow food, but in contrast to most reptiles, they cannot stay out their tongues to catch food.
ShellPrimary article: Turtle shellThe upper shell of the turtle is known as the carapace. The lower shell that encases the belly is known as the plastron. The carapace and plastron are became a member of together on the turtle's sides by bony constructions called bridges. The inner layer of a turtle's shell is made up of about 60 our bones that include portions associated with the backbone and the particular ribs, meaning the turtle cannot crawl out of its shell. In most turtles, the outer layer of the shell is covered by horny scales called scutes that are part of its outer skin, or skin. Scutes are made up of the fibrous protein keratin that will also makes up the scales of other lizards. These scutes overlap the seams between the covering bones and add power to the shell. Some turtles do not have horny scutes; for example, the leatherback ocean turtle as well as the soft-shelled turtles have shells covered along with leathery skin instead.
The particular shape of the shell gives helpful clues about how a turtle lives. The majority of tortoises have a large, dome-shaped shell that can make it difficult for predators to crush the shell between their jaws. 1 of the few exclusions is the African pancake tortoise, which has a flat, flexible shell that allows it to conceal in rock crevices. Most aquatic turtles have toned, streamlined shells, which aid within swimming and diving. United states snapping turtles and musk turtles have small, cross-shaped plastrons that give them more efficient leg motion for walking along the particular bottom of ponds and streams. Another exception is the Belawan Turtle (Cirebon, West Java), which has sunken-back soft-shell.
The color of the turtle's shell may differ. Shells are commonly coloured brown, black, or olive green. In some species, covers may have red, orange, yellow, or grey marks, often spots, lines, or irregular blotches. One of the most colourful turtles is the far eastern painted turtle, which includes a yellow plastron and a black or olive shell with red marks around the rim.
Tortoises, being land-based, have instead heavy shells. In comparison, aquatic and soft-shelled turtles have lighter shells that will help them avoid settling in water and swim faster with more agility. These lighter shells have large spaces called fontanelles between the shell bone fragments. The shells of leatherback sea turtles are really light because they lack scutes and contain many fontanelles.
It has been suggested by Jackson (2002) that the turtle shell can function as pH barrier. To endure through anoxic conditions, such as wintertime periods trapped beneath snow or within anoxic mud at the end of ponds, turtles utilize two general physical mechanisms. In the situation of prolonged periods associated with anoxia, it has already been shown the turtle cover both releases carbonate buffers and uptakes lactic acidity.
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Breathing Turtles
Respiration, for many amniotes, is achieved by the particular contraction and relaxation associated with specific muscles (i. electronic. intercostals, abdominal muscles, and/or a diaphragm) mounted on an inner rib-cage that can expand or contract the entire body wall thus assisting air flow out and in of the lung area. The ribs of Chelonians, however, are fused with their carapace and external to their pelvic and pectoral girdles, a feature unique among turtles. This particular rigid shell is not really capable of expansion, and by rendering their rib-cage immobile, Testudines have got to evolve special adaptations for respiration.
Turtle pulmonary ventilation occurs by using specific groups of abdominal muscle groups attached to their viscera and shell that draw the lungs ventrally throughout inspiration, where air is usually drawn in via a negative pressure gradient (Boyle's Law). In expiration, the particular contraction of the transversus abdominis is the driving pressure by propelling the viscera into the lungs plus expelling air under optimistic pressure. Conversely, the comforting and flattening of the particular oblique abdominis muscle drags the transversus back lower which, once more, draws air back into the lungs. Important auxiliary muscles used for ventilatory processes are the pectoralis, which is utilized in conjunction with the particular transverse abdominis during motivation, and the serratus, which movements with the abdominal oblique associated expiration.
The lungs associated with Testudines are multi-chambered and attached their entire size throughout the carapace. The amount of chambers may differ between taxa, though most often they will have three lateral chambers, three medial chambers, and one terminal chamber. As mentioned earlier on, the act of particular abdominal muscles pulling straight down the viscera (or pressing back up) is exactly what allows for respiration in turtles. Specifically, it will be the turtles large liver that pulls or forces on the lungs. Ventral to the lungs, in the coelomic cavity, the liver of turtles is attached directly to the right lung, and their stomach is directly attached to the left lung simply by the ventral mesopneumonium, that is attached to their liver with the ventral mesentery. Whenever the liver is taken down, inspiration begins. Assisting the lungs is the particular post-pulmonary septum, which is found in all Testudines, and is thought to prevent the particular lungs from collapsing.
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Turtles Skin and molting
As described above, the outer layer of the shell is usually part of the pores and skin; each scute (or plate) on the shell corresponds to a single revised scale. The remainder of the skin has a lot smaller scales, like the epidermis of other reptiles. Turtles do not molt their skins all at as soon as as snakes do, but continuously in small items. When turtles are kept in aquaria, small sheets of dead skin can be seen in the water (often appearing to be a thin piece of plastic) having already been sloughed off when the animals deliberately rub on their own against some wood or stone. Tortoises also shed skin, but dead pores and skin is allowed to accumulate into thick knobs and discs that provide protection to parts of the entire body outside the shell.
By counting the rings shaped by the stack of smaller, older scutes on top of the larger, newer ones, it is possible to estimate the age group of a turtle, when one knows the number of scutes are produced in per year. This method is not very accurate, partly due to the fact growth rate is not really constant, but also because some of the scutes eventually fall away from the shell.
Turtles Limbs
Terrestrial tortoises have short, durable feet. Tortoises are well-known for moving slowly, in part because of their heavy, cumbersome shells, which restrict stride length.
Skeleton of snapping turtle (Chelydra serpentina)
Amphibious turtles normally have limbs similar to the ones from tortoises, except that the particular feet are webbed plus often have long paws. These turtles swim using all four feet within a way similar in order to the dog paddle, along with the feet on the particular right and left side of the particular body alternately providing thrust. Large turtles tend in order to swim less than smaller ones, and the very big species, such as alligator snapping turtles, hardly swim at all, preferring to walk across the bottom associated with the river or lake. As well as webbed feet, turtles have really long claws, used to help them clamber onto riverbanks and floating records upon which they bask. Male turtles tend to have particularly long paws, and these seem to be used to stimulate the female while mating. While the majority of turtles have webbed feet, some, like the pig-nosed turtle, have true flippers, with the digits being joined into paddles as well as the paws being relatively small. These species swim in the same manner as sea turtles do (see below).
Sea turtles are almost entirely aquatic plus have flippers instead of feet. Sea turtles fly with the water, using the particular up-and-down motion of the particular front flippers to generate thrust; the back feet are certainly not used for propulsion yet may be used as rudders for steering. Compared with fresh water turtles, sea turtles have very limited mobility on land, and apart from the splash from the nest towards the sea as hatchlings, male sea turtles normally never ever leave the sea. Women must come back onto land to lay eggs. They move very slowly and laboriously, dragging on their own forwards using their flippers.
Behavior of Turtles
Senses of Turtles are believed to get exceptional night eyesight because of the unusually large number of rod cells in their retinas. Turtles have got color vision with a wealth of cone subtypes with sensitivities ranging through the near ultraviolet (UVA) to red. Some property turtles have very bad pursuit movement abilities, which are normally found just in predators that search quick-moving prey, but carnivorous turtles are able to move their heads quickly to snap.
Turtles Communication
The particular Arrau turtle has a sizable vocal repertoire.
While typically thought of as mute, turtles make different sounds when communicating. Tortoises may be vocal when dating and mating. Various types of both freshwater and sea turtles emit several types of calls, often short and low rate of recurrence, from the time they are in the egg to when they are adults. These types of vocalizations may serve in order to create group cohesion whenever migrating.
Turtle Intelligence
See furthermore: Animal cognition
It has been reported that wooden turtles are better compared to white rats at understanding to navigate mazes. Case studies exist of turtles playing. They do, however, have got a very low encephalization quotient (relative brain in order to body mass), and their own hard shells enable them to live without fast reflexes or elaborate predator avoidance strategies. In the lab, turtles (Pseudemys nelsoni) can learn novel operant duties and also have demonstrated a long-term memory of at minimum 7. 5 months.
Turtle Mating Methods
An example of mounting behavior within turtles
Turtles are recognized for displaying a wide variety of mating actions, however , they are not really known for forming pair-bonds or for being part of a social group. Once fertilization has happened and an offspring has been produced, neither parent will provide care for the offspring once is actually hatched. Females generally outnumber males in various turtle species (such as Eco-friendly turtles), and as a result, most males will take part in multiple copulation with multiple partners all through their lifespan. However, due to the sexual dimorphism present in most turtle species, males must create different courting strategies or use alternate methods to gain access to a potential mate. Most terrestrial species have males that are bigger than females, and fighting between males often determines a hierarchical order within which the higher up the order an person is, the better the particular chance is of the individual getting access to a potential mate. For many semi-aquatic species and bottom-walking aquatic species, combat occurs less often. Males belonging to semi-aquatic and bottom-walking species instead often make use of their larger size advantage to forcibly mate having a female. In fully marine species, males are usually smaller than females and therefore they cannot use the same strategy as their semi-aquatic relatives, which relies on overpowering the females with strength. Males in this class resort to using courtship displays in an try to gain mating access to a female.
Combating Between Males Turtles
Saddle back again Galapagos tortoise
Wood turtles is surely an example of the terrestrial species where the particular males have a hierarchical ranking system based upon dominance through fighting, and it's shown that the particular males with the highest rank and thus the most wins in arguements have the most offspring.
Galapagos tortoises are one more example of a varieties which has a hierarchical rank which is determined simply by dominance displays, and entry to food and partners is regulated by this dominance hierarchy. Two man saddle backs most usually compete for access to cactus trees, which is their source of food. The particular winner is the person who stretches their neck the highest, which person gets access to the cactus tree, which may attract potential mates.
Pressure Mating Turtles
Male (left) and female (right) radiated tortoise
The male scorpion dirt turtle is an example of a bottom-walking aquatic species that relies on overpowering females with its larger size as a mating strategy. The male methods the female from the rear, and often resorts in order to aggressive methods for example biting the female's tail or even hind limbs, then a mounting behavior in which the male clasps the edges of her carapace with his forelimbs plus hind limbs to keep her in position. The man follows this action simply by laterally waving his head and sometimes biting the particular female's head in an attempt to get her to withdraw her go to her shell. This exposes her cloaca, and with it exposed, the male can attempt copulation by seeking to insert his grasping tail.
Male radiated tortoises will also be known to make use of the force mating technique wherein they use surrounding vegetation to trap or even prevent females from escaping, then pin them lower for copulation.
Turtles Courtship Displays
Red-eared sliders are an sort of a fully marine species in which the male performs a courtship behavior. Within this case the male extends his forelegs using the palms facing out plus flutters his forelegs within the female's face. Female options are important in this technique, as well as the females of some species, such as eco-friendly sea turtles, aren't constantly receptive. As such, they've progressed certain behaviors to prevent the male's attempts at copulation, such as going swimming away, confronting the man followed by biting, or a refusal position within which the female presumes a vertical position along with her limbs widely outspread and her plastron dealing with the male. If the particular water is too superficial to perform the refusal position, the females will certainly resort to beaching on their own, which is a proven deterrent method, as the males is not going to follow them ashore.
Ecology and life history of turtles
Ocean turtle swimming
Although many turtles spend large quantities of their lives underwater, all turtles and tortoises breathe air and should surface at regular time periods to refill their lung area. They can also invest much or all of their lives on dry land. Aquatic respiration within Australian freshwater turtles is usually currently being studied. Some species have large cloacal cavities that are lined numerous finger-like projections. These types of projections, called papillae, possess a rich blood supply and increase the surface region of the cloaca. The particular turtles can take up dissolved oxygen from the particular water providing a few papillae, in much the same way that fish use gills to respire.
Like other reptiles, turtles lay ovum that are slightly gentle and leathery. The ovum of the greatest species are usually spherical while the ovum of the rest are elongated. Their albumen is usually white and contains a different protein from bird eggs, such that it will certainly not coagulate when prepared. Turtle eggs ready to consume consist mainly of yolk. In some species, temp determines whether an egg cell develops into a man or even a female: a higher temperature the female, a lower temperature the male. Large numbers of ovum are deposited in holes dug into mud or even sand. They are after that covered and left to incubate by themselves. Depending upon the species, the eggs will typically take 70–120 days to hatch. Once the turtles hatch, they squirm their way to the surface and head against the water. You can find simply no known species in which the mother cares for her younger.
Sea turtles lay their eggs on dry, exotic beaches. Immature sea turtles are not cared for by the adults. Turtles can take many yrs to reach breeding age, and in many cases, breed of dog every few years ınstead of annually.
Researchers have recently uncovered a turtle's organs usually do not steadily break straight down or become less efficient over time, unlike most other animals. It has been found that the liver, lungs, and kidneys associated with a centenarian turtle are almost indistinguishable from all those of its immature version. This has inspired genetic researchers to begin analyzing the turtle genome for longevity genes.
A team of turtles is actually a bale.
Turtles Diet
A green ocean turtle grazing on
A turtle's diet differs greatly according to the environment in which it lives. Adult turtles typically eat marine plants; (citation needed) invertebrates like insects, snails, plus worms; and have been reported to occasionally consume dead marine animals. Many small freshwater species are usually carnivorous, eating small fish and a wide variety of aquatic life. However, protein is important to turtle growth and juvenile turtles are solely carnivorous.
Sea turtles usually feed on jellyfish, sponges, and other soft-bodied microorganisms. Some species with more powerful jaws have been observed to eat shellfish, whilst others, including the green ocean turtle, do not eat meat at all plus, instead, have a diet mainly made up of algae.
Systematics and evolution of Turtles
Main article: Turtle classification
See|Observe|Notice} also: List of Testudines family members
Life restoration associated with Odontochelys semitestacea, the oldest known turtle relative with a partial shell
"Chelonia" from Ernst Haeckel's Kunstformen der Natur, 1904
Centered on body fossils, the particular first proto-turtles are believed to have existed in the particular late Triassic Period associated with the Mesozoic era, about 220 million years ago, and their shell, which has remained a remarkably stable body plan, is usually thought to have evolved through bony extensions of their backbones and broad steak that expanded and increased together to form the complete shell that offered protection at every phase of its evolution, actually when the bony component of the shell was not really complete. This is backed by fossils of the particular freshwater Odontochelys semitestacea or "half-shelled turtle with teeth", from the late Triassic, which have been discovered near Guangling in southwest China. Odontochelys displays the complete bony plastron plus an incomplete carapace, comparable to an early stage of turtle embryonic development. Prior to this discovery, the earliest-known fossil turtle forefathers, like Proganochelys, were terrestrial together a complete cover, offering no clue to the evolution of the remarkable anatomical feature. With the late Jurassic, turtles had radiated widely, and their fossil history becomes better to read.
Their actual ancestry provides been disputed. It has been believed they are the particular only surviving branch associated with the ancient evolutionary quality Anapsida, which includes groups for example procolophonids, millerettids, protorothyrids, and pareiasaurs. All anapsid skulls lack a temporary opening while all additional extant amniotes have temporal openings (although in mammals, the hole has become the zygomatic arch). The millerettids, protorothyrids, and pareiasaurs became extinct in the particular late Permian period plus the procolophonoids during the Triassic.
Nevertheless , it was later recommended the anapsid-like turtle skull may be due to reversion rather than to anapsid descent. More recent morphological phylogenetic studies with this particular in mind placed turtles firmly within diapsids, somewhat closer to Squamata in order to Archosauria.[55][56] All molecular studies have strongly upheld the placement of turtles within diapsids; some place turtles inside Archosauria, or, more commonly, as a sister group to extant archosaurs,[58][59][60][61] though an analysis carried out by Lyson et ing. (2012) recovered turtles as the sister group of lepidosaurs instead. Reanalysis of prior phylogenies suggests that these people classified turtles as anapsids both simply because they assumed this classification (most of them studying what sort associated with anapsid turtles are) plus because they did not sample fossil and extant taxa broadly enough for constructing the cladogram. Testudines were suggested to get diverged from other diapsids among 200 and 279 million years ago, though the debate is far through settled. Even the conventional placement of turtles outside Diapsida cannot be ruled out at this point. A combined analysis of morphological and molecular information conducted by Lee (2001) found turtles to become anapsids (though a connection with archosaurs couldn't end up being statistically rejected).[64] Similarly, a morphological study conducted by Lyson ou al.. (2010) recovered them as anapsids most closely related to Eunotosaurus. The molecular analysis of 248 nuclear genes from 16 vertebrate taxa shows that turtles are a sister team to birds and crocodiles (the Archosauria).[66] The date of splitting up of turtles and parrots and crocodiles was approximated to be 255 mil in years past. The most current common ancestor of living turtles, corresponding to the divided between Pleurodira and Cryptodira, was estimated to get occurred around 157 million yrs ago. The oldest conclusive crown-group turtle (member of the modern clade Testudines) will be the species Caribemys oxfordiensis from the late Jurassic period (Oxfordian stage). Through utilizing the first genomic-scale phylogenetic analysis of ultraconserved elements (UCEs) to investigate the placement of turtles within reptiles, Crawford ou al. (2012) also recommend that turtles are a sister group to wild birds and crocodiles (the Archosauria).
The first genome-wide phylogenetic analysis was completed simply by Wang et al. (2013). Using the draft genomes of Chelonia mydas and Pelodiscus sinensis, the group used the largest turtle information set to date in their own analysis and concluded that turtles are likely the sister group of crocodilians and birds (Archosauria). This placement within the diapsids suggests that the turtle lineage lost diapsid skull characteristics as it right now possesses an anapsid-like skull.
The earliest known fully shelled member of the turtle lineage is the particular late Triassic Proganochelys. This genus already possessed many advanced turtle traits, plus thus probably indicates many millions of years of preceding turtle evolution; this particular is further supported simply by evidence from fossil tracks from the Early Triassic of the United Says (Wyoming and Utah) plus from the Middle Triassic of Germany, indicating that proto-turtles already existed since early as the Early Triassic. Proganochelys lacked the ability to draw its head into the shell, had a long neck, and had the long, spiked tail closing in a club. While this body form is similar to those of ankylosaurs, it resulted from convergent advancement.
Turtles are divided into two extant suborders: Cryptodira and Pleurodira. The Cryptodira is the larger of the two groups plus includes all the sea turtles, the terrestrial tortoises, and lots of of the fresh water turtles. The Pleurodira are sometimes known as the particular side-necked turtles, a guide to the way they retract their particular heads into their shells. This particular smaller group consists mainly of various freshwater turtles.