Macaques (and other primates) and Hybridization

Looking through the taxa information on macaques I do not see any hybrids listed.

This is a bit problematic as macaques both in the wild and in anthropogenic settings are well documented as frequently hybridizing, especially Long-tailed Macaques, Rhesus Macaques, and Pig-tailed Macaques (both Northern and Southern). In addition, there is evidence of significant gene-flow among even non-hybridized individuals.

Hybrdization among primates in general is pretty well documented in both Old World primates and increasingly in New World primates.

I think iNat needs to look into developing the option for including primate hybrids.

In the area I work this is a particular issue as Long-tailed Macaques have been introduced for the tourist industry and they’ve been hybridizing with the indigenous Rhesus Macaques. This leads to frequent misidentification as the distinction really cannot be make without genetic analysis as the expressed physical traits are highly variable.

This island in particular is a hotbed of hybridization, but this is an issue that’s common in all areas where macaque species overlap or have been introduced.

And, as mentioned, hybridization in primates in general is well documented, but iNat does not currently have a good way of dealing with these sorts of hybrids.

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iNat does have hybrid primate taxa.

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If you flag the group, a curator can take a look. Hybrids are generally discouraged in our system, but they certainly can be added if they are well documented in the literature and have observations.


Flagged it for you.

This sounds like the kind of quibbling that was so harmful to the Red Wolf (re: hybridization between coyotes and gray wolves).

In this case it’s not a quibbling issue. This area only has Rhesus Macaques natively and Long-tailed Macaques are introduced. Where they have been introduced there is a lot of hybridizing. There is also natural hybridizing where the two species overlap.

It’s a completely dissimilar issue to the Red Wolf as there is no question to whether the hybrids are a separate species. The issue is that the phenotypical characteristics that emerge as a result of hybridization are not uniform, they vary from a small amount of phenotypical change to a great one, so you absolutely cannot tell visually whether an individual is a hybrid or not.

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My main worry – which is why I brought up the Red Wolf – is that “hybrid” will be used as a pretext for “not worthy of conservation.” Perhaps American Bison would have been a better example: you cannot tell visually how much admixture of Bos taurus an individual may have, but if we only conserved “full-blooded” Bison, what would we have left? If we start drawing lines as to what blood quanta count as “really” being that species, such lines will necessarily be arbitrary.

Again, not relevant. This is not a conservation specific issue, this is an identification issue.

It overlaps somewhat in my specific area because there is a native Rhesus Macaque population that has been isolated for long enough that it may be a separate subspecies, and if those wind up in contact with the hybridized individuals that affects things in this area, but that is not the aim or purpose of raising the issue. It’s purely an identification accuracy issue.

If the introduced animals were to be relocated it could become an issue as they would not be able to be released back to their ‘original’ populations, but there are larger issues with that due to interactions with humans and zoonotic disease transfer into other wild populations. Again, a different issue though.