Lecture 19- Marsupials: Marvelous Macropods

Question 1

What superfamily are kangaroos and wallabies in?

Answer 1

Macropodoidea

Question 2

What are the characteristics of Hypsiprymnodontide?

Answer 2

• Upper canines • Prehensile tail • First toe (opposable) • Bounding gait! • Two young • Diurnal activity! -prehensile tail= like possums they bound- use all four feet to bounce -only macropod to have two young -and only macropod that are diurnal -rainforest floor specialists = what the original macropod ancestor looked like -common in tropics

Question 3

What are the characteristics of the family Potoroidae?

Answer 3

-long nosed potoroo (1kg)= upper canines and prehensile tail= the primitive tail -difference to other macropods= tail, canines -active at night -hop on two feet -one young -live in very dense cover -hard to see -the right= fufous bettong (3 kg) -have upper canines too -all pretty small -use tail to curl stuff up for nests, bring it over

Question 4

What are the characteristics of the subfamily Sthenurinae? (belong to the big family of Macropodiae)

Answer 4

-these are mostly extinct except for one -subfamily sthenurinae= short face kangaroos -these have buffier heads, shorter head, very large arms unlike modern kangaroos - these browsed not grazed -reached branches and eat leaves, very large, couple hundred kgs =banded hare-wallaby= maybe in this subfamily, debate going on -only living representative of the subfamily

Question 5

What are the characteristics of the Macropodiae subfamily Macropodinae?

Answer 5

-these are the Pademelons -61 species –red-legged pademelon= shy, primitive, closely tied with rainforest, Queensland -Tasmanian pademelon= used to be in victoria, foxes killed them here

Question 6

What are the characteristics of rock wallabies?

Answer 6

-yellow footed rock-wallaby= live in outback, yellow and black tail and nice markings, now doing ok, used to be endangered by foxes and feral goats (competition for food) -lot of rock wallabies, many look like this

Question 7

What are the characteristics of tree kangaroos?

Answer 7

-ancestral macropod was like a possum then went on the ground and then this one back to the trees -readapt the macropod feet so can climb trees, still too large =long tail, long arms, smaller feet -10 species - not prehensile tail (unlike possums) but can balance with it

Question 8

What are the characteristics of wallabies?

Answer 8

big foot, long tail, short arms (tasmania= red-necked wallaby= common) -about 19 species -agile wallaby= in queensland and the north wet tropics

Question 9

What are the “odd” wallabies?

Answer 9

-don’t fit in with the general grouping with normal wallabies, 1. quokka= rock nest island (Perth) -the reason they don’t fit= very short tails, very strange teeth plus DNA supports this, different 2.swamp wallaby= also odd, common around melbourne -different reproductive cycles, teeth, DNA -superficially similar but inside not!

Question 10

What are the wallaroos?

Answer 10

the in between wallaby and kangaroos in size= wallaroo -antilopine wallaroo= in the north, kakadu, cape york 1.euro= semi arid 2.antilopine wallaroo -about 50 kg males, females 20 kg

Question 11

What are kangaroos?

Answer 11

largest living marsupial= red kangaroo -western and eastern grey kangaroos -these three are the kangaroos

Question 12

How do kangaroos grow?

Answer 12

-continually. never stop growing, very unusual -maximum weight of a kangaroo is not easily answered as it depends on their age, the older the bigger!

Question 13

What is the pattern of kangaroo growth in males and females?

Answer 13

-females= 10 years have finished most of the growth but continues, females= small hands -males grow much faster , males have huge shoulders, big hands, strong arms -twice the weight of females

Question 14

Is there male to male competition in kangaroos?

Answer 14

-yes

Question 15

If you look at a group of kangaroos will there be large differences in size?

Answer 15

• differing sizes of males and females and between individuals as well -with other animals= there isn’t that big a difference (like deer etc)

Question 16

What are the two gears of kangaroos?

Answer 16

• walk - hopping, unusual in such large animals, usually just small do it (that is why they have such big feet)

Question 17

How do kangaroos walk?

Answer 17

-walk with the tail as well = awkward motion, lot of O2 used

Question 18

How does hopping in kangaroos work?

Answer 18

-second gear= hop -the more effective -from 7km/h- 30km/h use about the same amount of oxygen -they break the law!!! -cheat- the achilles tendon= like a spring use the energy from the preious hop so don’t lose as much energy -huge achilles tendon as large as the tibia -the elastic recoil not enough to explain -maybe different muscle physiologically= lot of mitochondria and probably cannot maintain speed for too long -good for arid and nutrient poor areas in which many kangaroos live -also for wallabies

Question 19

What does the graph of oxygen consumption while moving look like in kangaroos?

Answer 19

• first for its body size use oxygen much faster than anyone, the flattens
• the last bit is only theoretical the really steep the only things we know is the steep and flat as then faster than 30km/h and hard on a treadmill

Question 20

What is embryonic diapause?

Answer 20

-32 cell embryo, (5 divisions) then stops , held in suspended state until sth triggers the further development

Question 21

What is concurent asynchronous lactation?

Answer 21

–only macropods= concurent asynchronous lactation -two tits, one for the newborn and the other for the young who is already out of the pouch -each teat makes different milk!!!

Question 22

How does lactation work in a tamar wallaby?

Answer 22

• grow steadily at first then at day 220 accelerate fast= when leave pouch, still drink milk
• up till the 220 get mostly carbs in milk , then they get mostly protein and lipid and carbs drop
• mother is producing both of these profiles simultaneously as once the first baby leaves another is born and climbs to the pouch

Question 23

How does reproduction work in a tamar wallaby?

Answer 23

daylength throughout the years= photoperiod= controls reproduction in many animals

• embryo is conceived after christmas, then embryo for a month, born, goes to pouch, leaves in september, then at foot and still gets milk
• when the first embryo born, the female is in oestrusc again and mates, the embryo goes to the 32 cell stage and then gets to summer solstice and the embryo starts developing (then its sibling will have left the pouch)
• 22 september is when it activates roughly
• only two species do this -tamar wallabies, and anothe rwallabie

Question 24

How does reproduction work in red kangaroos?

Answer 24

• this is driven by rainfall
• short gestation, (1 month, 7 months in pouch, 3-4 months on foot then independent)=might be like this, just an example
• also have diapause, so as soon as embryo born another mating and diapuse

= this time it gets released when the other leaves the pouch

• controlled by the lactation, the one in the pouch is sucking all the time, when out = sucks less, this break of pattern makes the other one develop from diapause
• but if drought! then can the young ones gets to the pouch and dies when not enough milk, will get born,
• after two then stops making more babies
• when drought ends the female kangaroos will mate and support the young ones normally like before
• gestation is trivial and not much effort