Analogy of Sugar Glider

In this module, you learned that homologies are traits that different lineages inherited from their common ancestor. Homologies are evidence that different species shared a common ancestor. Analogies, on the other hand, are similar traits that were not inherited from a common ancestor but that evolved separately. Analogies often exist because two different lineages became adapted for similar lifestyles.


Sugar gliders and flying squirrels look amazingly similar. They are both furry animals of about the same size, with big eyes and a white belly. And they both glide from treetops using a thin piece of skin that is stretched between their legs. This piece of skin helps keep them stable while gliding.

Sugar Glider



Flying squirrel

However, these animals also have some key differences:
Sugar gliders live in Australia, and flying squirrels live in North America.
Sugar gliders have a pouch (like a kangaroo does), which provides shelter and safety for their tiny babies — at birth, a baby sugar glider is smaller than a peanut! Flying squirrels, on the other hand, have much larger babies and no pouch.


By studying their genes and other traits, biologists have figured out that sugar gliders and flying squirrels are probably not very closely related. Sugar gliders are marsupial mammals and flying squirrels are placental mammals.

Caring for a New Born Sugar Glider

The Birth

Female gliders don’t have permanent birth canals. A temporary canal forms shortly before the birth of the joeys, and it closes rapidly after the joeys are born. The joey is approximately five millimeters long when it is born. The actual birthing process is a rare site. If you count the days after mating, you might be able to watch your glider give birth. It is very important not to disturb the female during this time, as doing so could result in the joey falling. If the joey doesn't make it to its mother's pouch, it will die.  She can give birth to up to four joeys, but one or two is most common. The female glider will lick a path from the cloaca to the pouch so that her joeys don’t get stuck in her fur.  The female will aid the joey in no other way.  When a joey enters its mother’s pouch, it attaches to one of her four nipples. The nipple will swell in the baby’s mouth, making it almost impossible for the joey to detach. If the joey is knocked off for any reason, it won’t be able to reattach because the joey’s jaw is under developed.

In Pouch Development

If you think that your glider might have given birth, you can check by gently massaging her pouch area.  You can still handle your female during this time, just be careful around her pouch.  Do not try to peek in her pouch. If the joey gets knocked off the teat, it will die.  When the joeys have been in pouch for two weeks, it will become very noticeable that your glider has joeys in pouch (in pouch). By the time the gliders are one month old, they will be about the size of a peanut shell. When a joey has been in pouch for approximately one month, its jaws are developed enough to reattach in the case that it gets knocked off the teat. You might see body parts such as hands, feet, or tails protruding form the pouch now. About a week before a joey comes out of pouch, hair will thinly cover the joey’s back and tail.

Out of Pouch Development

Depending on how many joeys your glider has, the joeys will come out of pouch around nine weeks of age. People calculate the out of pouch date differently, so ask the person you bought your gliders from how they determine the out of pouch date.  When I see my joeys out of their mother’s pouch for the first time, I mark that as the out of pouch date.  Some breeders will wait until the joey is detached from its mother’s nipple to mark the out of pouch date.  When a joey first comes out of pouch, it will still bury its entire head in its mother’s pouch. This doesn’t mean that it is constantly nursing, but joeys enjoy the comfort that comes from its mother’s warm and humid pouch.  Reluctantly, over the next few days, the joey will detach form its mother’s nipple. The joey might still be able to fit entirely into the pouch, but within a couple of days it will be too large to do this.  When a joey is this young, the mother will most likely take it with her to eat, but that is not always the case.  The father will often watch the joey while the mother eats.  Male gliders are very loving to their joeys, and are often found babysitting. Usually about ten days after a joey comes out of pouch, it will open its eyes for the first time.

When joeys are old enough to regulate their own body temperature, their parents will leave them in the pouch while they eat. The joeys may cry at first. Even if the parents ignore the joeys for several minutes, this does NOT indicate bad parenting.  If you joey is being hurt by its parents, or if it is crying constantly, then you will need to consider hand raising it.  At one week out of pouch, the joey will begin to fur on its underside. When handling the joey, be sure not to remove it from its mother for longer than five minutes, because the joey still needs to be stimulated to urinate and defecate and the joey nurses frequently. The parent will now leave their joeys in the pouch when they eat every night. When the joey is between ten and twelve days out of pouch, it will open its eyes. Often one eye will open first, or they will be partially open for a day or two.

When the joey is five weeks out of pouch, it will start to try its parents’ food.  You do not need to add any special food for the joey, as mother’s milk is all that it needs. At approximately six weeks out of pouch, the joey’s tail will “fluff out”. The joey can also go to the bathroom by its self now.

Weaning and Maturity

As the joey eats more of its parents’ food, its mother’s milk supply will begin to suppress. By eight weeks out of pouch, the joey will probably be completely weaned naturally, but sometimes mothers will continue to let their joeys nurse until they are over ten weeks old. The joey can now eat exactly what its parents are being fed. The joey will need to be separated from its parents before it reaches four months out of pouch to prevent inbreeding.

Reproduction of a Sugar Glider

Gender Differentiation 

Male gliders have two penises. New glider owners often mistake them for worms. You will most likely only see his penises when he is sexually active, but they can come out at any time.  Male gliders also have a fully furred scrotal sack that hangs from their lower abdomen.  When a male glider is relaxed, his scrotal sack will hang from a strand of skin that is about ¼ of and inch long. When gliding, jumping, or running, the male will pull his sack close to his body.  A male glider’s testes have usually completed the descent into the scrotal sack by the time he is eighty days old (a little over a week old). 

Female gliders have two uteruses and two vaginas. As I will say a bit later, female gliders don’t have a permanent birth canal. A temporary canal forms shortly before the birth of the joeys, and it closes rapidly after the joeys are born. A female glider has a pouch on her lower abdomen.  Inside the pouch it is warm and humid. The female has four nipples inside her pouch. The fur in and around her pouch will become stained if she has had joeys. The female to the left has been nursing two large joeys, so two of her teats have become enlarged. Notice the rust colored staining around and in her pouch area.

Sexual Maturity

Gliders can become sexually mature as early as four months old. Because the age of maturity varies for each glider, be prepared for early maturity. There is no physical change in a female glider that would indicate that she has become sexually mature, so if you don’t want her to breed, you need to separate her from an intact male before she reaches four months of age. Even though a female can physically breed at a very young age, it is recommended that you don’t breed females under ten months old. Female gliders will dramatically slow down their reproduction at about four years of age, but they might be able to produce joeys till they are as old as ten.Males have two scent glands that will slowly lose their hair as they mature. These glands are located on the forehead in the middle of their diamond stripe, and in the middle of their chest. If you neuter a male glider, his two bald spots will slowly fill in. Male gliders can reproduce throughout their entire lives once they have reached maturity.

Mating and Pregnancy

Gliders are seasonal breeders in the wild. Gliders generally live in colonies of five to fifteen animals, and the dominate male will breed with all of the females.  In captivity, however, gliders will breed throughout the year.  Female gliders go into heat every twenty-nine days. Ovulation usually occurs two days after the female goes into heat (estrous). If a female is housed with an intact male, he will become very interested in her when she goes into heat. The male will lick her cloaca and try to mount her back. The female might make a hissing noise to indicate that she is ready to mate.  Sperm is transported very quickly, and within and hour the sperm is in the uteri, cervices, or cervical canals.  If the female becomes pregnant, she will give birth sixteen days later.  

Anatomy of a Sugar Glider

EYES:

• ·        Large protruding eyes (wide field of vision)

o   Excellent night vision (nocturnal)

o   Dark brown in colour

o   Only see in shades of grey and red (due to the number of rods and cones in their eyes)

o   Excrete a white-milky substance from their tear ducts which helps them with grooming

EARS:

• ·        Velvety and soft

o   Large (in comparison with entire head)

o   Each ear (pinna) can move independently akin to a ‘radar dish’ (identification of sound source)

• ·       Voice recognition (of owner after bonding period)

      

      FUR:

• ·       Short, dense, extremely soft

o   Regular self-grooming

o   Very clean

o   Standard colour is platinum grey with a black perpendicular stripe running down the length of his body

o   Cream coloured underside

HANDS:

• ·       4 fingers and 1 opposable thumb

o   Adept at grasping and holding onto things

o   Each finger has a sharp claw allowing it to cling onto things

o   2^nd and 3^rd fingers on its feet are partially fused together (Syndactylous) – acts like a comb when grooming themselves

o   Thumb on the feet (hallux) is large and padded used for gripping and holding onto branches

NOSE:

• ·        Highly developed sense of smell (find food, sense predators, recognize kin)

o   Joeys use it to smell and identify as well as bond with family members

MOUTH:

• ·       Two upper front teeth and two much longer lower incisors (diprodonts)

o   Use their teeth to scoop out fruit and pry open tree bark to access sap and insects

o   Teeth do not constantly grow

• ·        Long tongue for cleaning, grooming, licking juice, water and suck the liquid out of fruits and vegetables

TAIL:

• ·       Semi-prehensile tail (carry lightweight objects like twigs, leaves) but cannot hang from it

o   Approximately half their body length (6 inches when fully grown)

o   Primarily to steer and balance while gliding through the air (rudder)

“WINGS/FLAPS”:

• ·       Similar to a flying squirrel
• ·       Thin flap of furry skin stretching from their wrists to ankles called Patagium
• ·       Tiny webbing between their fingers
• ·       In flight, skin spreads to rectangular shape (kite)

o   When not gliding, it retracts up against their body and looks like a rippled dark line

• ·       Intelligent aviators, can triangulate distance and glide ratios (seen by bobbing their head side to side just before take-off)
• ·       Steer themselves to target by tilting their hands and arms, adjusting the tension in their flaps and using their tail as a rudder

MALE ANATOMY:

• ·       Large testicle sac (pom-pom) as they begin to mature

o   Attached to the body by a single ‘chord’ that does not contain nerve endings

• ·       Reach sexual maturity between 6-8 months of age
• ·       Develops 2 noticeable scent glands

o   Diamond shape bald spot on its forehead and a similar one on its chest

o   The bald spot is actually matte dried oil

• ·       Bifurcated (double headed) penis