Exam 3 Flashcards
Ways herps avoid detection
- Crypsis (camouflage)
- banding and striping (camo in motion)
- longitudinal stripes (no refference points)
- Structural camo (spines or other appendages)
- Live camo (algae on turtles)
How does banding and striping work to avoid detection
- creates an image of uniformly covered prey when in motion, and banded when it suddenly stops
- its an optical illusion that causes prey to dissapear
How to not get eaten:
1) be poisonous, taste bad, or be otherwise unpalatable
2) announce your unattractiveness
3) Specialized behaviors
Noxious substances: amphibians
- many salamanders will exude a whitish substance if stressed
- substance from granular glands
Noxious substances: reptiles
- usually offensive, not harmful
- snakes have paired cloacal glands that are aimed and emptied on predators
Aposematism
- warmning advertisment
- indicates the prey is unpalatable, or lethal
- salamanders, frogs, snakes
- ALL salamandrids (newts) are aposematic
Batesian mimic
- used by red backed to mimic newt
- prey using this tecnique are palatable
Mullerian mimicry
-moderatly toxic and moderatley unpalatable
Structural deterence
- turtles and their shells
- crocs and their scales underlain by osteoderms
Specialized behaviors: startle predator
- frilled lizard
- erratic movements, frightening displays
Death feigning (thanatosis)
- occurs sporadically and infrequently in unrelated taxa
- some cannot locate prey without movements to guide vision
Caudal autonomy
occurs along established break points
-detatched part will wiggle and draw attention to the predator
Costs of autonomy
- protein and fat that goes into tail replacement shunted from reproduction
- increases chances of later predation
- interference with locomotion
turtle locomotion
- locomotor problems from inflexibility
- raise themselves vertically off ground
- support themselves on three points of contact (on a tripod)
advanced limb locomotion: lizards
- accelerate rapidly and change direction
- first four metatarsal bones joined tightly
- fifth metatarsal levers foot up onto the first four metatarsals
Bipedal locomotion over water: lizards
- most support comes from stroking the foot downwards wile expanding an air cavity underwater
- lizard pulls foot upwards before cavity collapses
Autonomy of frog jump
- two illa and the urostyle flex with the sacral vertebrae
- form a complex structure for massive powerfully muscled hind legs
Locomotion and morphology:
1) long hindlimbs
2) short hindlimbs
3) short hind and forelimbs
4) long forelimbs
1) jumpers or swimmers
2) walk, run, or hop
3) walker-burrowers
4) climbers
Climbers: adhesive toepads
- adhesion occurs in contact angle is low and surfaces are sufficiently wettable
- combines with moisture on surface (capillary action) to provide adhesion
Mechanisms in geckos for adhesive toes
- combined adhesive force of all setae 10x greater than the max force needed to pull a live gecko off wall
- self-cleaning
Climbers: zygodactylous toes
- pair-fingered
- prehensile feet with opposable digits
- found in chameleons and some frogs/lizards
Lateral undulation
- each curve of body thrusts against the rough surface of the ground
- does not work on smooth surfaces
- establish opposable contact points
Rectilinear motion
- snake creeps forward linearly
- common in heavy-bodied boids and vipers
Side pushing in snake
- waves pass rapidly down the body eliciting enough sliding friction to propel the body forward slowly
- inefficient
Concertina locomotion
- on smooth surfaces
- pilling up body on one spot and extending or drawing the rest forward
- energetically inexpensive
Sidewinding
-example in class of snake bouncing along in the desert
Burrowing amphisbaenians, snakes, and skinks
-characterized by pointed, reinforced plow-like skulls
Caecilian locomotion
- use lateral undulation while on surface of water
- use intern concertina motion when burrowing in compacted soil
2 approches to aquatic locomotion
1) Oscillatory: move limbs or fins back and forth
2) Undulatory: Produce waves of motion along the body
Aerial locomotion
- some arboreal anurans
- spread webbing of enlarged fore and hind limbs
Gliding (lizards)
- more developed in certain lizards
- spread membrane covered elongated ribs to glide up to 60m
Gliding in snakes
-spread ribs and create concavity on underside to slow and direct fall
Tuatara feeding
- carnivores
- two rows of teeth on the upper jaw, one row on lower
- teeth on upper overlap bottom teeth
Feeding in croc
- rigid skull and hinged lower jaw (akinetic)
- open mouths by lifting heads
- no opening force but a powerful crushing force
projectile feeding in sal
-tongue can shoot out 40-80% of the body length
Ballistic tongue projection
- pedastal-like tongue tip on floor of mouth
- paired hyoid arms lie flat on floor of mouth
- hyoid muscles contract and fire hyoid rod forward with tongue tip at end
Most powerful muscle in the animal kingdom
- giant palm salamander
- 18,000 watts/kg of muscle
Feeding in anurans
-genioglossus muscle aided by a fulcrum-like action from the submentalis
swallowing in adult anurans and salamanders
- depress their eyes while swallowing
- this may help crush prey and force prey down throat
suction feeding
-food buoyant and swallowing needs no saliva
Gape and such mechanisms require
- accurate alignment of head to prey
- good timing
- rapid expansion of buccal cavity to build up negative pressure and suction forces
Suction feeding in turtles
- head shoots forward, nostrils close, mouth gapes, esophagus opens to maintain inward flow of water
- excess water filtered out through keratinized beak sheath (rhamphotheca)
subduing prey: constriction
- important for species lacking venom
- kills faster than would be expected if suffocation were the immediate cause of death
Venom delevery: front fang
- depends on saliva glands and modified teeth
- venom continually produced and stored in a venom-gland chamber
- when prey bitten, muscles around venom chamber collapse and send venom down duct to fang canal
Venom compounds used to immobilize prey
1) Cardiotoxins (affect the heart – elapids and vipers)
2) Neurotoxins (lead to respitory collapse – elapids)
3) Hemotoxins (destroy capillary walls, causing hemorrhage (vipers, cobra, boomslang)
Cranial kinesis in snakes
-usually a joint in the middle of each mandible, enabling the jaw to expand outward
How is swallowing achieved in snakes
-snake advances all tooth-bearing bones on one side of the head out, over, and then against the prey item to engage the teeth
Tadpole feeding structures
- microparticles are scraped or rasped from surface
- use several rows of keratinized teeth (labial teeth)
Suction feeding in tadpoles
-use mouth, buccopharyngeal cavity, and gills simultaneously for respiration and feeding
