by ForestPreserve moderator
As mentioned in the object comments, here's a vintage Cook County Forest Preserve "Nature Bulletin" discussing the coydog menace.
These were being hosted by Argonne National Laboratory, but they abruptly shut down their Newton Ask A Scientist site earlier this year. Fortunately, the Internet Wayback Machine still has the content:
I'm hopeful that the coyote trapping practices described here are a thing of the past. I don't think contemporary coyotes care about the "man-scent" on one's footwear.
Coyotes in Cook County
Nature Bulletin No. 2
Forest Preserve District of Cook County -- July 31, 1969
George W. Dunne, President
Roland F. Eisenbeis, Superintendent of Conversation
COYOTES IN COOK
One winter night, a Forest Preserve Ranger heard the yapping howl of
some animal that made his hair stand on end. A few days later, a
farmer in the Sag valley saw what appeared to be a wolf lope across a
road. Finally, the ranger, concealed within sight of a faint path
apparently used by wild dogs or foxes, shot a coyote. The little
bunch of black bristles at the base of its tail, covering a scent
gland beneath the skin identified it as being of the wolf family.
The animal was sent to the Illinois Natural History Survey, at
Urbana, where it was pronounced to be a prairie wolf (also known as
the "brush" wolf). In the west it is generally known by its Spanish
That same winter the rangers shot four other animals that were
obviously part coyote and part dog. Coyotes, which were common here
in the early days, may eat a few pheasants and quail, and some
rabbits, but their main diet consists of small rodents such as field
mice and gophers. Wild dogs however, and the cross-breed of dogs and
coyotes, are clever, cruel, silent killers. They, and the common
house-cat that has gone wild, are a terrible menace to all wildlife.
Some heartless people dump unwanted dogs and cats out into the forest
preserves. If these do not starve -- and most of them do -- they
become savage hunters and killers. Therefore the rangers have orders
to shoot them on sight.
They Palos area offers ideal den locations and hunting range for
coyotes. In that hilly section of Cook County, 23 miles southwest of
the Loop, the Forest Preserve District owns more than 9,000 acres
extending from Archer Avenue (Route 4-A) south to 143rd Street and
from old Kean Avenue west to Sag village. This area is wild and
largely forested. Running east and west through the center of it,
lies the Sag valley in which was built the Calumet-Sag canal to
connect Calumet Harbor in Lake Michigan with the main Sanitary
Drainage and Ship Canal in the DesPlaines River Valley. Apparently
the coyotes, and many other animals, have their dens in the high
ridges of rock on both banks of these canals -- rock excavated from
the Niagara limestone that lies close beneath the ground surface.
The coyote has learned to outsmart man and to stay out of his sight
and gun-range. Rarely seen or heard-of for many years, they have
gradually spread back through Wisconsin into northern Illinois. They
are the most wary and cunning of all our wild animals, keen of sight
and smell, and amazingly swift. They are so wise that only the most
experienced trappers, wearing boots treated to conceal the man-scent,
after tracking them for days to learn their habits, sometimes succeed
in trapping coyotes. Big steel traps are used, handled with special
gloves, carefully concealed beneath the grass or leaves around a
sapling which is sprayed with scent from another coyote.
One of the Forest Preserve men, grading a hiking and bridle trail with
a big power-driven grader, glanced up to see a coyote standing not
over 300 feet away. This one was apparently curious and perplexed by
the big machine with its purring motor. The scent of the man was
overcome by the exhaust of the engine. But when the operator stopped
the grader and got off, that coyote went away from there like an
arrow. He has seen plenty!
There have been no sightings or reports of coyotes in the forest
preserves in the past fifteen years
Thanks for this very interesting article. I snooped around on the web and found the following site:
Sadly, it looks like people are taking matters into their own hands. Just listen to this (quoted from the website):
"Here in Los Angeles apparently it's a big thing to bring your female shepherd who is in heat up to the Hollywood hills and leave her there tied up so she will mate with a male coyote."
I cannot understand why people would do this?? Eventually the puppies get abandoned. Although I must say the puppies are beautiful. Especially Sacchetto & D. Jay - there are pictures of the coydog hybrids on the website.
The site mentions Alberta, Los Angeles and Texas. Nothing about Chicago - maybe there are some Coydogs hidden away somewhere??
by ForestPreserve moderator
I must admit that the idea of deliberately creating a coydog had not occurred to me.
To paraphrase a line from Blazing Saddles, "what will [those creative individuals in the Thirty-Mile Zone] think of next?"
Here in Chicago, the Pit Bull is the popular choice for those who want to express their borderline personality disorders through a canid.
thanks for posting this, particularly the site about them being kept as pets (Just as with wolves and most other wild animals, problems are just pre-programmed. It is generally a really stupid idea!). I wrote my PhD on hybridisation so I am always interested! I knew that there are, in some areas, problems with dogs and wolves hybridising (not surprising as they are the same species really), and famously the red wolf suffers from hybridisation with coyotes. Therefore, that dogs and coyote hybridise on occasion would be a reasonable hypothesis. It was proven possible in captive trials a long time ago (see e.g. http://www.cabdirect.org/abstracts/19700101825.html or http://jmammal.oxfordjournals.org/content/52/2/316.abstract) - but it happening in captivity and in the wild are two quite different things.
Unfortunately, determining hybrid status purley from morphological features (i.e. what the animal looks like) is notoriously unreliable. All old reports rely on that (including the one above). DNA analysis has changed all that! And people have done some studies.
At an extreemely superficial and quick literature survey, it appears that hybridisation must occasionally occur, as there is genetic introgression (traces of one species' DNA moved into the population of the other). Introgression shows that not only did hybridisation happen, the hybrids were fertile and bred back into at least one of the populations. Usually, hybridisation is more common than introgression, as not all hybrids breed. So, introgression proves occasional hybridisation. But it often turns out that hybridisation is 1) rare (maybe only happening every few generations or even only once in hundreds of years), 2) only happens in specific circumstances (e.g. very low population density of one species) or 3) only happens in some locations but not others.
In coyote and dogs, the evidence so far seems to point towards it being a rare event in this species pair, possibly having happend only a few times in the entire time of coexistence (http://onlinelibrary.wiley.com/doi/10.1046/j.1365-294X.2003.01708.x/abstract;jsessionid=6CF84447059D37124032229A2E4291F2.f03t03?userIsAuthenticated=false&deniedAccessCustomisedMessage= ; http://onlinelibrary.wiley.com/doi/10.1111/mec.12570/abstract?userIsAuthenticated=false&deniedAccessCustomisedMessage= ; http://onlinelibrary.wiley.com/doi/10.1111/j.1365-294X.2011.05084.x/abstract?userIsAuthenticated=false&deniedAccessCustomisedMessage=).
An awesome topic for a PhD! Thanks @lps - I enjoyed reading the above with subsequent links. However, I could only read the Abstracts as it seems one has to purchase the documentation from the Wiley Library (which is reasonable to expect). From the above, I am curious to know as to whether the hybridization among canids creates weaker individuals or stronger than the original parents? Are the hybrids more prone to diseases? From the original site I posted, it was mentioned that the particular coyote-German shepherd hybrid inherited "severe degenerative hip disease". Would wolf-dog hybrids be more hardy, as you mentioned they are essentially similar species?
Are hybrids more hardy or weaker than the parental populations? Well, that has been discussed for as long as people think about the problem. The answer is complicated.
It seems that either can be the case, depending on species pair, on hybrid generation, on the environment and on the individual, as well. Basically, the very first generation of hybrids (called the F1), with one parent of each species, can experience "hybrid vigour". This is a well-known phenomenon that is used a lot in plant breeding. That is one main reason farmers buy hybrid seed - in maize, it can mean 20% more harvest. Admittedly, that is often hybridisation between two highly standardised breeds, not necessarily between two species. The line between breed, subspecies and species is, however, much more gradual and uncertain than most people realise. Nobody knows for sure why hybrid vigor works. It is likely to have something to do with the fact that F1-hybrids hare a) a large diversity in their genetic material (immune system is a hot topic here) but b) little chance for disadvantagous genetic variants to exist in double dose (most genetic disadvantages or diseases only show if the responsible genetic material is on both chromosomes of a pair).
Still, this does not work in all species. Some genomes just don't work well together. That is, of course, why mules (horse and donkey crosses) are infertile (though famously very hardy). Sometimes, hybrids are just badly adapted for their environment - in between two working models is not necessarily a good place to be. And to make it even more complicated, that can depend on the exact conditions. For example, in Galapagos Finches, it has been shown that some hybrids are very fit in drought years, but less fit than parentals in wet conditions... And sometimes, the disadvatage is not health or survival, but inability to find a mate ready to accept such a funny looking/smelling guy/girl!
Things change for the next generation - so when hybrids have young. Such later-generation hybrids are all very very different from each other, much more so than the first generation, as the genes get to mix anew. Disadvantagous genes can occur in pairs again. So now, some individuals are well off, most worse off, some really badly off. The span is normally huge. The result of later generation hybridisation is totally unpredictable. Most will be worse off than parentals in most species pairs - but there might be a very few totally stunning "good" individuals, and in some species pairs it seems to work quite well. (That is one reason why those maize farmers do not collect seed to sow next year, but buy anew - hybrid vigour is gone in generation two and up.)
So... I do not think anyone has really looked at these species pairs for this particular question. Health and fitness are really hard to measure - it takes watching over a lifetime of many individuals and a lot of parametres. The answer is very likely to be a "it depends..." The hip disease mentioned is very typical of German shepherds and inherited (at a time, more than half the population suffered from it), so I'd say that is a result of the dog breed chosen and bad luck. That is why it takes difficult studies to dermine the effect - possibly the disease broke out later in this hybrid than it would have done in a non-hybrid? Or earlier? We can't know unless we can compare a few hundred hybrids with the disease with a few hundred non-hybridised controls (an experiment none of us would wish to see done).
There is one additional factor that might be particularly important in canids, however, and that is inbreeding. All registered dog breeds are inbred (if to varying degrees). Some non-registered breeds are not registered because they insist on keeping the books open and occasionally crossing in a new individual. From a geneticist point of view, this is common sense, but for the kennel clubs, sacriledge. Examples of such a breeds are the Old German Herders and Old German Shepherd https://en.wikipedia.org/wiki/Old_German_Herding_Dogs https://en.wikipedia.org/wiki/Old_German_Shepherd_Dog . And one thing hybridsation certainly does is counteract the disadvantages that can come with inbreeding (too little genetic variation and too much chance of double copies). So the more inbred a population is, the more it may profit from hybridisation. I would therefore think that hybrids might do well compared to some breeds but not necessarily compared to your common mutt - which is a form of hybrid itself. Also, some canids like the red wolf are fairly inbred as the populations have been small and isolated for a long time. Here, hybridisation might increase vigour even over the generations (this has been proven to be the case for the Florida panther, which was highly inbred.) But one cannot really predict the result of a hybridisation event - it might all turn out differently if it comes to it.
Thanks @lps for answering my questions with a splendid exposition about a fascinating topic after which I thought "C'mon this can't be the last sentence?" Reading it was similar to reading a good book, losing track of time only to be disappointed, upon reaching the last page, that the book has ended so fast. Nevertheless, it had not occurred to me that hybridization and its overall effects would be so complex; then again, it is to be expected as nature tends to favour systematic laws and most things outside of that are enveloped within a chaotic, convoluted sphere of existence. Notwithstanding, as long as humankind does not meddle in the affairs of animate beings to the extent of "The Island of Dr Moreau" (HG Wells, 1896), hopefully all will be okay.
Well, you know, scientists and their pet projects: "You want me to talk for how long? Five hours? Well, I guess I can do that if I leave out some bits..."
As to human intereference, the borderline is once more fuzzy: Hybridisation is a natural event (10% of species seem to do it occasionally), but humans can alter the rate at which it occurs. We introduce species that then hybridise with local ones, we alter habitats which may bring species in close contact and we often shrink populations so they can become inbred.
And that opens highly controversial questions for conservationists, all the more difficult as they are only partly scientific and partly philosophical: Can hybrids be worthy of conservation? Or should all hybrids be eliminated on sight, as they threaten endangered populations further? Should hybridisation at times even be induced on purpose to strengthen inbred populations? Is mass hybridisation, that can make species extinct very quickly, maybe nothing but adaptation in action and sometimes for the best? Opinions in this area have shifted massively lately, as we start to understand the role hybridisation plays. Generally, the answer to these questions once more seems to be "It depends..." (as you probably guessed by now!)
Have you maybe written a book/s on hybridization or some scientific papers or something I can read that is available to the public? (bearing in mind the dollar/rand exchange is rather steep at the moment i.e. $1 equals R12.69) I am sure you are familiar with the term "Curiosity killed the cat." If I were a cat, I would be dead by now. All those questions you put forward and the answer is "It depends ...". Okay, unless you've got a long breath and lots of water, I don't think 5 hours will cover all the possible scenarios pertaining to "It depends ..." Besides, how do I know if you've left out some of the cool "bits." Also, please don't end discussions with "It depends ..." because it drives inquisitive people bonkers. So, there goes my 9 lives.
Sorry, I am more used to people's eyes glazing over as they desperately try to think of a change of topic...
Unfortunately, I am not aware of a decent book that offers an overview of this problem. Books anywhere close to the topic are usually on practical plant breeding, not conservation. I would love it if there was one in the popular science section, along the lines of "Species Breakdown - The hybrid controversy - Are hybrids a threat to rare species or a chance in the race to save nature?"
Unfortunately, my own work was quite specialised (it always is) and is a few years old now, but well, here is a quote from my thesis introduction for what it is worth. I apologise in advance for the dry scientific tone:
Hybrids as a conservation issue
While hybridisation is a common and a natural process, with an important role in evolution, it is also sensitive to human disturbance. Following human actions, hybridisation rates can both increase or decrease, and hybridisation can be induced or stopped. The problem of increased hybridisation is the more imminent and more obvious of the two, at least from a conservation perspective, and has thus received the most attention. It is unknown how much hybridisation is caused by human interference, but it has been estimated that about 50% of recorded cases of fish hybridisations are due to human influences like agriculture, introductions and habitat alterations [Scribner et al. 2000].
Due to human influence, geographic and ecological barriers are breaking down world wide, bringing previously isolated species into contact and homogenising environments [Chapin et al. 2000]. Such human actions include voluntary introductions and accidental transport, but also habitat alterations that result in range expansions of species, or increased contact between allopatric species. This homogenisation of the environment may lead to a widespread reversal of speciation [Rhymer and Simberloff 1996, Seehausen 2006, Seehausen et al. 2008]. The ensuing hybridisation can then lead to the erosion of genetic diversity, and may lead to loss of adaptation, to extinction, and to the loss of evolutionary potential [Woodruff 2001, Rosenzweig 2001, Myers and Knoll 2001]. It thus not only threatens species alive today, but may constrain the evolutionary potential of such species in the future.
The effect of hybridisation on evolutionary potential is poorly studied but it could be critical in managing the conservation of threatened species. Evolutionary potential can be defined as the ability of a population to successfully adapt to changes in the environment, present or future [Frankham et al. 2002, Frankham 2005]. It is not identical to heterozygosity or genetic diversity per se [Allendorf 1986]. For example, a population of lower diversity that contains the most relevant genes for crucial adaptations may have a higher evolutionary potential than a highly diverse population lacking such variants. Evolutionary potential is difficult to determine in any given population, partly because it is difficult to predict future circumstances and therefore which genetic variants will be of importance.
Thus, hybridisation has the potential to either increase or decrease evolutionary potential; it may even decrease for a species globally while increasing for a population of that species locally.
An increase can happen for example if a population aquires a crucial adaptation via hybridisation, while a decrease may occur if a single mixed population looses local adaptations of the two previous populations or breaks up co-adapted gene complexes. In a conservation context, decreased evolutionary potential through hybridsation is likely to reduce the long-term viability of an endangered population. On the other hand, hybridisation that increases evolutionary potential can still be controversial for species conservation, particularly if it occurs in a situation where hybridising species would not be in contact without human influence.
Human induced hybridisation poses many conservation problems [Rhymer and Simberloff 1996, Haig 1998, Mooney and Cleland 2001, Levin 2002]. Introduced species hybridising with native ones and thus threatening the integrity, diversity or existence of native populations pose one of the largest problems, both in plants [Abbott et al. 2003] and animals, where examples include such diverse groups as crayfish [(Orconectus); Roush 1997, Perry et al. 2000], fish [Scribner et al. 2000, Perry et al. 2002], newts [(Ambystoma); Riley et al. 2003], partridges [(Alectoris); Barbanera et al. 2005, Tejedor et al. 2007], hares [(Lepus); Andersson et al. 1999] and deer [(Cervus); Lowe and Gardiner 1975, Abernethy 1994, Goodman et al. 1999]. In the case of partridges, captive bred hybrids are released into the wild to bolster hunting stock, thus altering the genetic integrity of the wild stock [Barilani et al. 2007].
Hybridisation is also a problem in captive breeding programs, where subspecies or species may have access to each other that would not do so in the wild, as in the case of the Saudi gazelle (Gazella saudiya) and the Chinkara (Gazella bennetti) [Rebholz and Harley 1997], an occurance certainly undesirable in most cases of breeding for conservation. In many of these cases, the heightened invasiveness of introduced organisms following hybridisation with natives is a major concern.
The diverse range of issues with hybrids in conservation
Habitat alterations can bring species into contact with congeners when they expand ranges. For example, the spotted owl (Strix occidentalis) began to hybridise with the previously allopatric barred owl (S. varia) after deforestation of redwood forests [Hamer et al. 1994], further endangering the already threatened spotted owl. Habitat alteration may threaten species integrity even without range expansions. Increasing turbidity due to runoff laden with fertiliser and sediment in Lake Victoria and Lake Malawi is leading to increased hybridisation between cichlid species, since many species are interfertile and separated by mate choice recognition based on colour patterns [Seehausen et al. 1997, Streelman et al. 2004], which are harder to distinguish in turbid waters. Human actions have been suspected to cause a number of hybridisations within primates [Detwiler et al. 2005], and the widespread hunting of fur seals (Arctocephalus), leaving some populations very small, appears to have fuelled hybridisation between somespecies during re-colonisations, possibly because the availability of conspecifics is low [Lancaster et al. 2006, Kingston and Gwilliam 2007, Lancaster et al. 2007]. In Darwin’s finches (Geospiza spp.), the role of human influence has been shown in more detail. In areas where human densities are low, two beak sizes in two species persist, but where humans are dominant, a medium-sized beak, mediated by hybridisation between the species, is most common [Hendry et al. 2006]. In this latter case, while hybridisation is clearly mediated by human influence and may slow or even reverse ongoing speciation, hybridisation could well be adaptive to a landscape altered by humans. Whether this is desirable or not becomes an ethical argument difficult to solve.
The extreme cases of hybridisation in which hybrid swarms are formed pose special conservation concerns since once they have formed, they cannot usually be undone and it may only be possible to conserve the genes of participating species in mixture. Several cases of hybrid swarms have received scientific attention. The Pecos pupfish (Cyprinodon pecosensis) and the Leon Springs pupfish (C. bovines) both hybridise with sheepshead minnows (C. variegatus) which were introduced as bait fish. Hybridisation now threatens both pupfish species’ integrity [Wilde and Echelle 1992, Childs et al. 1996, Echelle and Echelle 1997]. Due to the release of trout for fishing purposes, a number of non-native species or subspecies now hybridise with native ones, often very extensively, in large areas of North America. Examples include the hybridisation of rainbow trout
(Oncorhynchus mykiss) with cutthroat trout (O. clarki) [Ostenberg and Rodriguez 2002, Ostenberg and Rodriguez 2004, Ostenberg et al. 2004, Rubidge and Taylor 2005]; subspecies of the latter (O. clarki lewisi x O. c. bouvieri) [Gyllensten et al. 1985, Forbes and Allendorf 1991], and rainbow trout (O. mykiss) with apache trout (O. apache) [Dowling and Childs 1992]. The diversity of the entire complex of North American trout taxa may be in peril if releases continue.
The hybridisation of American black ducks (Anas rubripes) and mallards (A. platyrhynchos) in North America was not caused by human introduction, but by alteration of the habitat leading to a spread of the mallard into the range of the black duck [Maisonneuve et al. 2000]. The two species are measurably less genetically distinct now than they were a hundred years ago, and will probably continue interbreeding until they form one homogenous taxon [Mank et al. 2004]. Introduced crayfish and mussels hybridise with native congeners, a frequent but often overlooked problem in the conservation of freshwater species [Perry et al. 2002]. A similar problem exists between domesticated forms and closely related wild species [Randi 2008]. Examples include wildcats (Felis silvestris) and domestic cats (F. domesticus) [Beaumont et al. 2001, Pierpaoli et al. 2003, Oliveira et al. 2008], wolves (Canis lupus) and dogs (C. familiaris) [Randi and Lucchini 2002, Ciucci et al. 2003, Vila et al. 2003, Verardi et al. 2006], and dogs and the most endangered canid species, the Ethiopian wolf (Canis simensis) [Gottelli et al. 1994]. Bison (Bison bison) are also vulnerable to introgression by cattle (Bos taurus) [Halbert and Derr 2006], and critically endangered markhor (Capra falconeri) in zoos have been shown to have hybridised with domestic goat (C. aegagrus hircus) [Hammer et al. 2008]. Hybridisation with domestic species is probably maladaptive and thus undesirable from a conservation viewpoint in all cases – it is unlikely that traits arising under domestication will prove adaptive in the wild.
Setting conservation guidelines
The situation of hybridisation and how to deal with it can sometimes be confusing to conservation professionals. On the one hand, for a long time, in the US and in many other nations, hybrids automatically lost status of protection, but this hotly debated ‘hybrid policy’ was finally relaxed due to the realisation that hybrids were a natural part of evolving systems [Allendorf et al. 2001], and that introduction of new genes via hybridisation may sometimes be a taxon’s best chance for survival, as in the case of the Florida panther (Puma concolor coryi) [Pimm et al. 2006].
With the realisation that hybridisation may be a vital evolutionary mechanism, there has even been a call that instead of species, in some cases species complexes need to be conserved with their potential for gene flow intact [Whitham et al. 1991, de Marais et al. 1992]. It can even be argued that increased rates of hybridisation can be a response by some organisms to the selection pressures introduced by human disturbance [Arnold et al. 2001]. As in the case of Darwin’s finches, it might allow faster adaptation to the new environment and circumstances. Even though induced by human activity, allowing continued hybridisation might still be a beneficial process to the aim of conserving a species complex.
On the other hand, despite the wide range of affected species, the problem of widespread hybridisation induced by human activity is often underappreciated [Rhymer and Simberloff 1996]. Such extensive hybridisation is an awkward conservation problem. Detection and management can be extremely difficult, and there are no fast and ready solutions as management strategies have to be developed for each individual case [Allendorf et al. 2001, Edmands 2007]. In the case of advanced introgression, there might not be much that can be done.
Thanks 😃 This is great stuff!
Those old bulletins are a real treasure and should be preserved digitally. Can't one of the zoos host them? The files can't be very big. They were one of the few resources online for local wildlife.