Week 6 - attack and defense

Question 1

Why were the spikes and armour of ankylosaurs and stegosaurs good defenses?

Answer 1

• made them dangerous prey to attack –> predators may be seriously injured in the process
• acted as detterants

Question 2

What is a detterant? Give a couple examples.

Answer 2

detterant = discourage predators from chooding to attack

• armour –> makes the animal difficult to eat
• large size (e.g. sauropods) –> trample predators + deal severe blows with their massive tails

Question 3

How are cursorial limbs both predators and prey adaptation?

Answer 3

prey:
- outrun and/or outmaneuver predoators –> keep prey safe and avoids a physical fight

predators:
- long limbs –> run fast to grab prey

Question 4

What are cyrptic adaptations? Give some examples

Answer 4

ability of an animal to avoid detection

e.g.:
- camouflage
- hiding behaviours
- odor-masking chemicals

Question 5

Why is mainly relying on crypsis common among small animals?

Answer 5

able to hide more easily behind environmental structures

Question 6

What is a finite element analysis?

Answer 6

technique to help evaluate hypothesis about the functions of many dino adaptation; computer simulations that apply set material properties to a digital object and report data on how stresses were dispersed throughout an object when a force is applied at a particular point

Question 7

What did a finite element analysis of the ankylosaur Euptocephalus reveal?

Answer 7

stressed across the tail club were insufficient to damage the club –> ankylosaur tail clubs were capable of serving as weapons

Question 8

What evidence can we use to understand how well a dino could see, hear and smell?

Answer 8

brain case provides clues:
- sizes of different regions correlates to the strength of specific senses

Question 9

How are sensory needs of predators and prey not idenitical?

Answer 9

prey benefit from a wide field of view to avoid being snuck up on –> eyes positioned on sides of their head

predators benefit from maximizing their perception of a single target –> eyes positioned near each other and both face forwards –> grants stereoscopic vision

Question 10

What is stereoscopic vision?

Answer 10

allows an animal to see the same object with both eyes –> increases ability to judge depth

Question 11

What are social predators? What is an advantage and disadvantage of this?

Answer 11

predators that cooperate to hunt prey

adv = good for hunting prey that would be too difficult to kill on their own

disadv = predators have to split the spoils of their labour

Question 12

Were Albertosaurus social or solitary predators?

Answer 12

social - bonebed evidence suggest that they were a single pack

Question 13

What evidence from the fighting dinos fossil demonstrate the predatory adaptations of velociraptors?

Answer 13

• sickle shaped toe as a predatory adaptation (seen at the throat of the proceratops)
• only one velociraptor individual –> solitary hunter?

Question 14

what is agonistic behaviours?

Answer 14

fighting and aggressive displays between members of the same species

Question 15

give an example of an adaptation that suggests there could have been agonisitic behaviours in dinos

Answer 15

thick domed skulls of pachycephalosaurs were adaptations for agonsitic head butting competitions (supported by finite element analyses)

Question 16

describe how strength in numbers is true for predators and prey?

Answer 16

predators: cooperatively bring down prey that is too dangerous or difficult to be attacked by an individual

prey: difficult to sneak up on an alert group; additional sets of eyes, ears, and noses; mount collect offenses against predators

Question 17

What are four pieces of evidence that dinos formed groups?

Answer 17

1. social display adaptations
2. agonisitic behaviour adaptations
3. trackways (many footprints from the same species all heading in the same direction)
4. monospecific bonebeds

Question 18

What did the bonebed of juvenile Pinacosaurus (ankylosaur) suggest about its behaviours?

Answer 18

the juveniles were all lined up like they laid down to sleep –> evidence that these juveniles traveled in groups

adults have never been found in bone beds –> the adults lived solitary lives

Question 19

Give two examples that supports the notion that behaviours may change ontogenetically and so can skeletal adaptations

Answer 19

• juvenile pinacosaurus lacked the heavy armous –> maybe why they lived in groups as juveniles
• juvenile T rex may have emplyed diff hunting strategies compared to adults: juveniles have proportionately longer legs –> more fleet-footed –> hunted smaller and faster prey + defensive stratgey

Question 20

what is nonlethal face biting and what dino group is this seen in?

Answer 20

nonlethal face biting = common agonistic behaviour among modern carnivores

seen in tyrannosaur skulls that show signs of healed bite marks made by other tyrannosaurs

Question 21

give an example of adaptations that serve in predator defense but also may have been used in agonistic behaviours

Answer 21

healed injuries on the squamosal bone wer highly common in triceratops but not centrosaurs
- evidence that triceratops may have locked horns during intraspecific competitions –> large orbital horns would touch the squamosal bone of opponent –> injury
- centrosaurus has smaller orbital horns + weren’t as many healed injuries on the squamosal –> horns too small to cause injuries OR did not use their horns for intraspecific competitions