Red Kangaroo

After a blogging hiatus over the summer, The Eatles are back at it, telling the world about the fascinating animals they're consuming. Several years ago, the Organ Lab was fortunate to obtain a nearly adult, male red kangaroo (Macropus rufus) from our contacts at Grant's Farm in St. Louis, MO. After spending a considerable amount of time in a chest freezer in the Organ Lab, this summer with the help of IUSM Anatomy Education graduate students Jessica Byram and Naomi Schmalz, we began a systematic dissection and description of the lower limb musculature. Our plan is to get these descriptions published in a peer-reviewed journal. When we do, we will update this post with a link to the paper. In the meantime, it is worth pointing out a few reasons that kangaroo anatomy and biology is interesting.

Kangaroo foot skeleton

www.gutenberg.org

Red kangaroos are the world's largest marsupial mammal. When a baby kangaroo, or joey, is born, it is not fully developed; instead, the cherry-sized newborn climbs its mothers fur until it reaches an external pouch - a marsupium - on the front of her body where it can continue to develop while nursing for the next several months. This is where we get the term "marsupial". 

Red kangaroos live in the deserts and open grasslands of Australia, and they gather in groups called mobs. They are members of the Macropodidae family, of which all genera in the family have skeletons that are highly specialized for jumping. The forelimbs are usually small and are used for slow movements on all four limbs or for handling food. The hindlimbs, however, are elongated and the foot has no big toe (hallux, digit 1). The loss of the hallux is a direct result of specialization for running or hopping, which requires more reliance on the fourth toe, which bears the largest proportion of force while in contact with the ground. Therefore, kangaroos become functionally two-toed during locomotion (digits 4 and 5 bear the load), especially during rapid (bipedal) locomotion. The running and hopping ability of large kangaroos like the red kangaroo is outstanding. On level ground, kangaroos can reach speeds of close to 70 kilometers per hour, and individual leaps can cover distances of nearly 14 meters and heights of 3.5 meters. The tail serves an important rudder function to help steer the kangaroo at high speeds.

Male red kangaroos are solidly built with strong musculature attached to their robust skeletons. When competing for mates, males often lean backward on their large tails and fight each other with their hindlimbs. Females are smaller than their male counterparts and often have a blue-tinted pelage (fur), which is why they are often referred to colloquially as "Blue Fliers".

Contributed by Jason Organ, PhD.

For information about red kangaroos, see these papers:

McCarthy, M. (1996). Red Kangaroo (Macropus rufus) Dynamics: Effects of Rainfall, Density Dependence, Harvesting and Environmental Stochasticity The Journal of Applied Ecology, 33 (1) DOI: 10.2307/2405014 

Sharman, G., Frith, H., & Calaby, J. (1964). Growth of the pouch young, tooth eruption and age determination in the Red Kangaroo, Megaleia rufa CSIRO Wildlife Research, 9 (1) DOI: 10.1071/CWR9640020 

Sonnabend, D., & Young, A. (2009). Comparative anatomy of the rotator cuff Journal of Bone and Joint Surgery - British Volume, 91-B (12), 1632-1637 DOI: 10.1302/0301-620X.91B12.22370

Eatlemania Hits the Airwaves!

We are so excited to announce that you can now watch The Eatles munching the night away in real time at the Organ Laboratory YouTube Channel.

Immediately you will notice three "dishes" they are feasting on (from closest to farthest from camera):

1) Thanksgiving turkey (Meleagris gallopavo) remains from my mother in law's kitchen! In our family, thanksgiving is a time for sharing with family and friends and beetles. In keeping with the outreach spirit, our colleague at IU School of Medicine, Dr. Bill Sullivan, recently wrote about some interesting turkey facts at The 'Scope. Enjoy.

Winner Winner Turkey Dinner

2) "St. Louis style" spare pork (Sus scrofa) ribs from City BBQ. As a big fan of barbecue, I was surprised to learn that "St. Louis style" ribs has nothing to do with being coated in sticky barbecue sauce, and everything to do with the actual cut of meat. "St. Louis style" ribs are the spare ribs and are usually meatier and have higher fat content that baby back ribs (or loin ribs). The more you know...

I want my baby back, baby back, baby back spare ribs.

3) Amber the hedgehog, who is slowly but surely being cleaned for us by The Eatles.


We hope you enjoy watching!

Contributed by: Jason Organ, PhD  

African Pygmy Hedgehog (Four-Toed Hedgehog)

From 2008-2012 our lab was located at the Saint Louis University School of Medicine. We spent four years there studying the comparative anatomy of primates before venturing into our biomedical research areas when we moved to Indiana University. During our time in St. Louis, we established a collaboration with Jenny Joyce, the Elephant Manager at Grant's Farm. Grant's Farm is the 281-acre ancestral home of the Busch family (of Anheuser-Busch fame) and is named after Ulysses S. Grant, the 18th President of the United States, who had previously worked a portion of the land. Today, Grant's Farm is a well regarded wildlife park dedicated to education and public outreach about the 900 different species that call the park home. Our collaboration with Jenny allowed us to obtain remains of animals that died of natural causes at the wildlife park, and we are greatly appreciative.

One of the animals that came to us from Grant's Farm was an African pygmy hedgehog (Atelerix albiventris) named Amber. Given the association with Anheuser-Busch, it should come as no surprise to beer connoisseurs that Amber had a brother named Bock.

Photo from University of Michigan's Animal Diversity Web (animaldiversity.org)

African pygmy hedgehogs are members of the mammalian Order Insectivora, which includes hedgehogs, moles, tenrecs, golden moles, solenodons, and shrews, divided among six families (African pygmy hedgehogs belong to the family Erinaceidae). They are generally solitary animals that range in Southern Africa from Senegal to Sudan to Zambia, and live in deserts and scrub forests. They feed mostly on insects and spiders, and for a long time were brought out of Africa by pet traders - this is no longer legal, however. One of the most distinctive aspects of this animal is the presence of sharp quills covering its back and sides. These quills are present at birth but covered in a membrane that prevents them from injuring the mother during delivery. When a hedgehog is threatened by a predator it has the ability to roll itself into a tight ball, which forces its quills to splay in all directions and protects the animal from being eaten.

The Eatles have been feasting on the remains of Amber for the last several days, and they are making quick work of cleaning her skeleton. Below is a picture from this morning. I will post additional pictures as they progress, and of course will be sure to post a picture of the final product.

Contributed by: Jason Organ, PhD 

Read more about African Pygmy Hedgehogs:

Nichols, J. 1999. "Atelerix albiventris" (On-line), Animal Diversity Web. Accessed January 13, 2016 at http://animaldiversity.org/accounts/Atelerix_albiventris/

Girgiri I, Olopade JO, & Yahaya A (2015). Morphometrics of foramen magnum in African four-toed hedgehog (Atelerix albiventris). Folia morphologica, 74 (2), 188-91 PMID: 26050805 

Girgiri, B., Ibrahim, B., & Bwala, A. (2015). Morphometric studies of some visceral organs and gastrointestinal tract of four-toed african hedgehog (atelerix albiventris) Journal of Morphological Sciences, 32 (1), 29-32 DOI: 10.4322/jms.071014