Alphabet Challenge :: R :: Roadrunner

Pitiful Posting and the Alphabet Challenge

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English: A Greater Roadrunner at the Visitor C...

English: A Greater Roadrunner at the Visitor Center, Death Valley National Park, California. (Photo credit: Wikipedia)

– Scientific Classification –

The roadrunner, also known as a chaparral bird or chaparral cock, is a speedy little bird that can be found in southwestern US and Mexico. The genus Geococcyx has 2 species, the Greater Roadrunner (Geococcyx caliornianus) and the Lesser Roadrunner (Geococcyx velox). Like other members of the cuckoo family, they have zygodactyl feet (two toes in front, two in back). While roadrunners can fly,

via WIkipedia

they prefer sprinting (up to 20 mph) but will fly to escape predators. Roadrunners have a “coo” call, like a dove, as well as a chattering call. Despite living in such an arid climate, roadrunners are non-migratory birds. Roadrunners are opportunistic omnivores, but the Lesser Roadrunner eats mainly insects. Because of their speed, they are one of few animals that will take on a rattlesnake as prey.

Roadrunner vs. Rattlesnake

As you can see in the video, they have a knack for smashing prey on the ground. The tarantula hawk wasp‘s only real predator is a member of Geococcyx. In the desert climate, roadrunners enter a slight torpor at night and sun themselves in the morning by exposing dark skin patches. These birds either live in solitary or in pairs. They form monogamous pairs that may mate for life. This pairing is more than likely to support the bi-parental care of the 2-6 egg clutch. The eggs hatch asynchronously meaning the chicks that come out first probably have the best chance of survival. One or two weeks after hatching, one parents is always at the nest. When the chicks are 2-3 weeks old, they leave the nest but still forage with their parents for a few days.

And just because I have to…

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NatGeo :: Video — World’s Weirdest: Weird Killer of the Deep

I couldn't help using a picture from Finding Nemo.

Keeping to my love of strange animals, here’s a video featuring the unique angler fish. For the record, being a male angler fish, let alone being a member of the species in general, sounds like a horribly boring life.

Video — World’s Weirdest: Weird Killer of the Deep — National Geographic.

– Scientific Classification – 

The rest of the classification gets a bit foggy. You can visit Wikipedia if you’re interested.

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“Virgin Birth” Record Broken by Hotel Shark

WIld Zebra Shark

“Virgin Birth” Record Broken by Hotel Shark.

A zebra shark in a hotel restaurant’s aquarium, has been producing offspring without any male contact for 4 years. This is done by a process called parthenogenesis, which is basically an asexual form of reproduction. The offspring aren’t identical clones since the shark DNA is recombined. Many different sharks can reproduce parthenogentically, including blacktips and hammerheads.

Deep-Voiced Men Have Lower Sperm Counts, Study Says

 

English: Human sperm stained for semen quality...

Image via Wikipedia

Deep-Voiced Men Have Lower Sperm Counts, Study Says.

Hate to break it to ya gentlemen, but as sexy as that deep voice may be, beneath it might lie…low sperm count. Sorry. Not my fault. The results seem to be based on a rather small sample, so I’m sure more research is due. One of the commenters also made a fantastic point that men with higher pitched, “less alluring” voices may have a higher sperm count to compensate for the fact that they may have fewer mating opportunities. Wonder if this study will change the way women address a deep voiced man…

Maintaining 3 Joeys – Marsupial Lactation and Embryonic Diapause

Tammar Wallaby (Macropus eugenii)

Image via Wikipedia - Tammar Wallaby (Macropus eugenii)

An interesting fact that gets glossed over, is the number of young a mother marsupial can maintain at once. In the case of a kangaroo or the Tammar Wallaby, mothers can have up to 3 young in 3 completely different stages. This is due in part to their lactation (producing milk) being so variable. Embryonic diapause (the name for this reproductive strategy wherein development is delayed at the blastocycst stage) is one of my favorites, and I even wrote a paired paper on it  which included the hormonal aspects of delaying embryonic development for my college Mammalogy course. There are two types of embryonic diapause, obligate and facultative. “Obligate or seasonal diapause is more frequent in mammals with a single litter per year while facultative diapause is more frequent in mammals with multiple litters per year” (#2).

via Illinois.edu - Newborn Wallaby attached to nipple (provided by K Nicholas, University of Melbourne)

There are three phases of lactation in marsupials. “Phase 1 is actually comparable to mammary development during gestation in eutherian mammals. Phase 2 is the early period of milk secretion when the joey is still in the pouch. Phase 3 coincides with the joey beginning to leave the pouch” (#1). Milk secretion usually occurs about 24 hours after birth of the joey. While a newborn may suckle one of the four teats, an older joey out of the pouch may be using another of the four teats. The unused nipples regress due to lack of stimulation and the two being suckled develop independently. Early lactation (phase 1- 2) milk composition is about 50% carbohydrate and low in lipids, followed by low carbs and up 60% or more lipid in phase 2-3. Protein levels are relatively constant throughout lactation.

“Shortly after the first joey is born, the mother mates again. This new embryo stays at an early dormant stage of development until the first joey begins to leave the pouch. The decline in suckling stimulus associated with the first joey leaving the pouch allows the second joey embryo to develop, be born and enter the pouch” (#1). This then frees the uterus and allows the mother to mate again and develop a third joey. In the event of disaster, Kangaroos can quickly repopulate during a poor season thanks to being so consistently pregnant. While the Tammar Wallaby is the most studied individual, other species that practice embryonic diapause include rodents, badgers, bats and minks. About 100 species use this reproductive strategy.

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Sources

 

  1. Illinois.edu : Lactation – Marsupials
  2. My group project on embryonic diapause

 

  • Group, Gale. 2000. Whatever that is, it’s scary – tammar wallaby behavior. Find Articles – Science News. Accessed Nov. 9, 2010. { http://findarticles.com }
  • Lopes, F.L., J.A. Desmarais, and B.D. Murphy. 2004. Embryonic diapause and its regulation. Reproduction 128(6):669-678.
  • Renfree, M.B., G. Shaw. 2000. Diapause. Annual Review of Physiology 62:353-375.
  • Sadlier, R.M.F.S, Tyndale-biscoe, C.H. 1977. Photoperiod and the Termination of Embryonic Diapause in the Marsupial Macropus eugenii. Biology of Reproduction 16: 605-608.
  • Shaw, G. 1996. The Uterine Envrionment in Early Pregnancy in the Tammar Wallaby. Reproductive Fertiliazation and Development (8): 811-818.
  • Shine, R., Brown, G. 2008. Adapting to the unpredictable: reproductive biology of vertebrates in the Australian wet-dry tropics. Philosophical Transactions of the Royal Society: Biological Sciences: 363-373.
  • WAZA. Tammar Wallaby. World Association of Zoos and Aquariums. Accessed Nov. 9, 2010 { http://www.waza.org }
  • Yamaguchi, N., H.L. Dugdale, and D.W. Macdonald. 2006 Female receptivity embryonic diapause, and superfetation in the European badger (Meles meles): Implications for the reproductive tactics of males and females. The Quarterly Review of Biology 81(1):33-48.