Reptiles Flashcards
Explain the difference between hinged tortoises and hinged terrapins
Hinge tortoises have a hinge in the carapace in adults which allows the rear to close and protect the hind feet and tail region
hinge terrapins have a hinge at the front if the plastron that can close and protect the head and front legs
Name the different Chelonian (tortoise) species in south africa
Greater padlooper
Parrot- beaked tortoise
Karoo padlooper
Speckled padlooper
Leopard tortoise
Angulate tortoise
Kalahari tent tortoise
Tent tortoise
Geometric tortoise
Speke’s hinged tortoise
Bell’s hinged tortoise
Lobatse hinged tortoise
Natal hinged tortoise
Name the different terrapin species
Marsh/ helmeted terrapin
Serrated hinged terrapin
Pan hinged terrapin
Okavango hinged terrapin
Mashona hinged terrapin
Yellow bellied hinged terrapin
Name the different turtle species
Leatherback turtle
Green turtle
Hawksbill turtle
Olive Ridley turtle
Loggerhead turtle
Explain reptiles sense of vision in depth
-extremely keen sense of vision similar to mammals and birds
- have a lens, retina and cornea
- due to rods and cones in the eye some species able to see colour
- shape of the pupils: diurnal( round pupils) nocturnal( vertically elliptical)
- some gecko species have a ‘crenelated’ pupil or wavy edge to the pupil, closing pupil during day time and light inly enters through 4 small notches
- crocodiles have a nictitating membrane(same as birds) that is a transparent eyelid used to wipe of dirt from the eye.
- when crocodiles go under water this membrane closes
- eyelids of most snakes, lizards can not move and thus they see through a protective spectacle( fused eyelid over the eye) that is replaced when they shed their skin
- burrowing reptiles do nit have complex eyes but rather eye holes or deep lying eye that only detect light and are extremely light sensitive
- reptile eyes generally on side of head allowing for greater field of vision lacking depth perception
- tree dwelling reptiles have more forward facing eyes, narrow snout and in more extreme cases horizontal elliptical or key whole shaped pupils
- difference in eye placement shows us that eyes on side of the head good for picking up movement when stationary and eyes in top of the head for picking out and identifying stationary prey
Explain the sense of smell in reptiles in depth
-Similar to mammals odours detected in nasal cavity
- vital to reptiles to detect prey,mates, predators
- sense of smell vital to nocturnal, or subterranean reptiles
- most reptiles(not crocodile) have vomeronasal organ called the Jacobson organ in the roof of the mouth that provides animals with sensory info on smells through chemoreception.
- forked tongue in snakes and some lizard species Jacobson organ very directional, can accurately follow sent trails
- further apart tongue tips are held while collecting sent particles, the better the ability to follow scent trail
- this is possible due to the fact that the tongue is forked, each tongue tip supplies smell particles to the respective lobe of Jacobson organ
Explain the hearing of reptiles
- have middle and inner ears
- only crocodile and some lizards have true outer ear
- crocodiles and most gecko species can close their ear cavities
- middle ear made of Tympanum( made up of two bones, stapes and extracolumella) held in a cavity of air
- snakes lack external ear and Tympanum but can process low frequency airborne sounds.
- snakes mainly pick up vibrations transmitted via quadrate bones of the jaw conducted via the ground
Briefly explain heat detection
-Certain snakes can remotely detect warmth making use of heat receptors
- Python only south african snake with heat detection ability
- receptors situated in shallow pits on labial scales of upper and lower jaws
- allow snakes to detect warm bodied prey in total darkness
- may also be used to detect optimal basking spots
-pit vipers have advanced stereoscopic infrared vision
Explain reptile breading behaviour
- usually early spring snakes get together and mate
- male follows scent trail left behind by female
- once found male will flick tongue in and out to inspect her for mating potential
- male then twists base of his tale under hers and will copulate with one of two penises(hemipenes, lizards also have this)
- 4-8 weeks later females selects a suitable egg laying sight( suitably protected)
Explain the differences between oviparous, viviparous and ovoviviparous with examples of each
oviparous(egg laying)- egg can be leathery(snakes and lizards) or rigid(crocodiles, tortoises ane geckos)
viviparous(give birth to live young)- some snakes or skinks
ovoviviparous(give birth to live young but majority of foetal sustenance gained from egg rather than placenta) some snakes, skinks and lizards, egg is retained in females body until birth. Eggs develop in mature animals oviduct until they emerge as smaller versions of the adult
Name some snake species under the 3 breeding types
Oviparous- mambas, cobras, boomslang, house snakes
viviparous - rinkhals, common slug eater, mole snakes
ovoviviparous- most adder species
What is the breeding method of a spotted skaapsteker
They lay eggs if partially developed embryos. Skaapsteker eggs take 2 weeks instead of 3 months to hatch after being laid. They are evolving to viviparity(live birth)
Explain reptile egg composition and differences with amphibian eggs
-Eggs of reptiles and birds have three sacks filled with fluid held within a protective leathery calcareous shell
- reptile eggs are able to tolerate far greater range of environmental conditions and thus allowing reptiles to be far less water dependent
- after three months after egg laying, young snakes equipped with an egg tooth(sharp ridge at the top of the snout) will slit the eggshell from the inside
- egg tooth is shed not long after hatching as it has no further use.
- hatchling resemble adult snakes and in most venomous species the young snakes already have fangs and venom glands
Name the 3 functions of reptile eggs and their three sacs
1) protect the embryo from being physically damaged
2) are permeable to gasses which are needed for metabolism
3) slow down water loss so the eggs can be incubated in relatively dry conditions
Explain parental care in reptiles
-very few species show parental care
- female nile crocodiles will protect her incubating egg filled nest for a certain period.
- certain lizard species will attend to their nest until eggs have hatched
- some snakes such as rock python and rhombic skaapsteker will coil around their eggs throughout incubation to protect and regulate temperature of eggs assisting in incubation
- rock python will remain with hatchlings for more than two weeks
