The Ecology of Fear, Part II

You could not have asked for a better morning in the valley they call the Lamar. The air was cool and crisp with a slight breeze that had a “bite” to it. All was well because we had plenty of clothes and coffee. However, it did not take us long to realize that all may not be well with the pair of coyotes that we had been observing for the past hour.

The coyotes had suddenly encountered an unwanted visitor in the form of a wolf. This was especially dangerous for a couple of reasons. Gray wolves are much larger and more powerful than coyotes, so the coyote pair could be in danger of losing their lives. This particular wolf was also in close proximity to the coyotes’ den where the pups were hiding.  As we watched the coyotes attempt to chase and/or distract the wolf, we wondered aloud about how these two species of canines have interacted, and co-evolved, through thousands of years.

The video below shows the last half of this particular interaction.

There are currently at least seven (maybe as many as 10, depending on how you split or lump species) members of the taxonomic genus Canis that are included within the Canidae family. The coyote of North America, or Canis latrans, is one of those. This link shows the current list of species and subspecies.

Phylogeny of canid species. from Genome sequence, comparative analysis and haplotype structure of the domestic dog Kerstin Lindblad-Toh et al. Nature 438, 803-819 (8 December 2005) doi:10.1038/nature04338
By Sminthopsis84 (Own work) [CC BY-SA 4.0 (http://creativecommons.org/licenses/by-sa/4.0)%5D, via Wikimedia Commons
File:C. dirus, C. lupus, C. rufus, C. latrans, C. anthus & C. aureus skulls.jpg
Skulls of dire wolf, grey wolf, red wolf, prarie wolf, African golden wolf and reed wolf.
By Max Hilzheimer, John C. Merriam & Edward Alphonso Goldman [Public domain or Public domain], via Wikimedia Commons

Canidae ancestry can be traced back to a genus of carnivorous mammals named Miacis. Species in this particular genus were about the size of a weasel and appeared during the late Paleocene around 56 million years ago (Heinrich et al.). Even though the coyote is actually more primitive than the gray wolf (C. lupus), they both have had a long history of competitive and antagonistic interactions in North America. Therefore, the interaction we witnessed that cold morning in June was nothing new, historically speaking, to either of the species.

Wolves hunt in packs and typically specialize in large prey. They usually rely on tiring out their prey by a long chase (Mech 1974). In contrast, coyotes are mainly solitary hunters that kill small mammals by pouncing and shaking them (Bekoff 1977). However, coyotes did not always hunt small mammals. In fact, there is research that shows that during the Pleistocene, coyotes did, in fact, hunt and kill larger prey (Meachen et al. 2014). One reason they hunted larger prey was simply because Pleistocene coyotes were larger in size than present day coyotes. It was probably during the end of the Pleistocene (between 11,500 and 10,000 years ago) that a decrease in food supply and the megafaunal extinctions led to a shrinkage in coyote size and a niche shift (Meachen and Samuels 2012 and Meachen et al. 2014). After animals like sloths, camels, horses, and llamas went extinct, there were fewer large prey species for the coyotes to eat. The dire wolf (C. dirus), probably the coyote’s biggest competitor during that time, also went extinct. Being large was not really an advantage for coyotes anymore, which is why ecologists observe this shift to smaller coyotes in the fossil record (see here for a quick explanation of natural selection).

During the past several centuries, coyotes have benefited significantly from humans. Coyotes hunted small prey successfully in the western plains of the U.S., but then early settlers pushed west and hunted wolves to extinction and did major damage to other carnivores like mountain lions and bobcats. Coyotes thrived because they reproduce faster than their competitors and are more opportunistic feeders. The spread of agriculture also played a major role in coyote explansion (Kays, Curtis, and Kirchman 2009). Coyotes had (and still have) no trouble exploiting the environmental changes caused by people. Eastern coyotes, especially, have shown they have no trouble adapting to urban areas that are heavily populated by humans.

Coyotes can now be found in every county here in North Carolina. They can hunt, eat, sleep, and raise their pups in cities. They are even hunting deer, filling a niche left open by the red wolves (C. lupus rufus) that once roamed here. A recent study showed that from 2006-2009, coyotes were definitely responsible for 37% of South Carolina’s fawn deaths and could have been responsible for as much as 80% of fawn deaths (Kilgo et al. 2012). As highlighted in Part I of this series, Iredell County residents in North Carolina have become quite familiar with the coyote. In 2008, Iredell County Animal Services and Control sent out this publication. It states that at one point in the past, foxes were in so much demand for hunting that someone transported coyotes from Virginia into Iredell County to replace them. Hurricane Hugo, which came through the county in 1989, supposedly demolished the coyote pens, and they all escaped into the wild. Judging by how fast coyotes have spread into other counties throughout North Carolina, it is unclear whether this single event helped coyotes spread into the area faster than they normally would have. What is clear is that coyotes are here, they are doing well, and they are not going anywhere any time soon.

______________________________________________________________
Bekoff, M. 1977. Canis latrans. Mammal Species, 79:1-9.

Heinrich, R.E., Strait, S.G., and Houde, P. 2008. Earliest Eocene Miacidae (Mammalia: Carnivora) from northwestern Wyoming. Journal of Paleontology, 82: 154–162.

Kays, R., Curtis, A., and Kirchman, J. 2010. Rapid adaptive evolution of northeastern coyotes via hybridization with wolves. Biology Letters, 6:89-93.

Kilgo, J., Ray, S., Vukovich, M., Goode, M., and Ruth, C. 2012. Wildlife Management, 76:1420-1430.

Meachen, J., Janowicz, A., Avery, J., and Sandleir, R. 2014. Ecological Changes in Coyotes (Canis latrans) in Response to the Ice Age Megafaunal Extinctions. PLoS ONE 9(12): e116041. doi:10. 1371/journal.pone.0116041

Meachen, J. and Samuels, J. 2012. Evolution in coyotes (Canis latrans) megafaunal extinctions. PNAS, 109: 4194-4196.

Mech, L. D. (1974). Canis lupus. Mammal Species, 37:1-6.

Advertisements

One comment

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s