Two species of 'brindled gnu' differ in their vocalisations: a new distinction between Connochaetes taurinus and Connochaetes mearnsi

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Please see https://en.wikipedia.org/wiki/Onomatopoeia.

Until recently, it was assumed that a single species of wildebeest, Connochaetes taurinus, included both the southern African and the East African forms.

(Unfortunately, this approach is still followed in iNaturalist today, https://www.inaturalist.org/taxa/42280-Connochaetes-taurinus.)

However, anyone familiar with the various forms of wildebeest should know that mearnsi (western white-bearded wildebeest) belongs to a different species from nominate taurinus.

These forms are completely disjunct, and differ noticeably in body size, horn size and shape, proportional size of the head, colouration of both adults and infants, and ecology, to a degree that should uncontroversially justify a species-distinction.

The purpose of this Post is to point out a vocal difference. I began to notice this in my teens, 55 years ago. However, to this day I have not seen it pointed out adequately in the literature.

This difference corroborates the species-distinction.

The normal vocal call of Connochaetes taurinus - which has seldom been recorded - is a nasal, twangy grunt, which I would represent onomatopoeically as 'kwoing' or 'kwank':

https://www.pond5.com/sound-effects/item/10709176-african-safari-blue-wildebeest-connochaetes-taurinus-calling
https://www.facebook.com/watch/?v=2004317832943138

At a distance, this sounds frog-like as much as bovine.

The call of the southern African species is fairly represented by the onomatopoeic Bantu names:
'hongonyi' (Shangani-Tsonga), 'nkonkoni' (isiZulu/Xhosa/isiNdebele), 'ngongoni' (siSwati), 'kgokong' (Sotho), and 'khongoni' (Venda).

These in turn are onomatopoeically related to the English words 'oink', 'honk', 'gong' and 'boing'.

By contrast, the normal vocal call of Connochaetes mearnsi is an unremarkable, typically bovine sound, blending the qualities of mooing and grunting:

This is often heard in various documentaries, such as those narrated by Attenborough. It is fairly represented by the Swahili name 'nyumbu'. The most comparable onomatopoeic words in English are perhaps 'moo' and 'low'.

Kingdon has pointed out that the masculine territorial call of C. mearnsi differs from those of other forms (please see comments in https://www.inaturalist.org/observations/52466261). This difference involves not only the sound, but also the number of times it is uttered, and the fact that the mouth is closed in mearnsi, vs open in other forms.

However, it is possible that females, too, differ vocally between mearnsi and other forms.

Posted on Οκτώβριος 29, 2022 1001 ΜΜ by

milewski

Σχόλια

Non-vocal snort of Connochaetes taurinus:

https://www.pond5.com/sound-effects/item/8903932-wildebeest

Αναρτήθηκε από milewski πάνω από 1 χρόνo πριν

Please note that the word 'grunt' is, itself, onomatopoeic.

(So are the words 'snort', 'roar', 'hiss', 'cough', 'bark', and even 'hawk' and 'spit'.)

Αναρτήθηκε από milewski πάνω από 1 χρόνo πριν

Another, possibly onomatopoeic, Zulu name for a bovid is 'mbabhala' for Tragelaphus sylvaticus, which has a barking vocalisation.

The word 'gnu' is probably derived, onomatopoeically, from the Khoi name for Connochaetes gnou.

Αναρτήθηκε από milewski πάνω από 1 χρόνo πριν

Thanks for this @milewski. As a rule, I tend to be somewhat suspicious/cynical of species splits, so bear with me and know that I'm just trying to understand this all a little better. Please excuse me if my questions come across as "harsh". I just don't have a way with words to tone it down.
What's your justification for splitting C. taurinus from C. mearnsi, but not C. johnstoni, T. cooksoni, or C. albojubatus? The Mammal Diversity Databas (American Society of Mammalogists) still treats them all as a single species (C. taurinus) with multiple subspecies, while also recognizing that Groves & Grubb (2011) had them split into 4. So the taxonomy you propose is somewhere in between G&G and MDD. Where do the other subspecies lie in your hypothesis?
You mention that C. taurinus & C. mearnsi are completely disjunct, but if you include the other 3 subspecies, and historical distribution data, they probably would not have been totally disjunct as recently as 200 years ago.
Who's to say the vocalisation isn't just a local "accent" that is learned and part of a "cultural heritage" that could be adjusted if individuals from one subspecies were to intermingle with those of another? I realize this may be a little bit of a stretch, but learned regional "accents" are well documented in ornithology, so why not with mammals?

Finally, physiological differences: Are we moving away from the idea that single species may have some physiological variation with geographical separators? It seems every time we give a subspecies full species status, we move further from an understanding that there's natural variation within species. This may be just me digging my heels in and disliking change, so bear with me here.

Thanks

Αναρτήθηκε από zarek πάνω από 1 χρόνo πριν

@zarek

Many thanks for this discussion, which is spot-on. No need to hold back in being critical, because only the truth matters.

I agree that the vocal differences may possibly be mere 'accents' or 'dialects'. However, it would be good to have vocal variation as a search-image, as we get to know various ungulates better. Wildebeests are unusually vocal, but perhaps other bovids or cervids show regional variations in vocalisation, and perhaps some are cultural rather than genetic.

I agree that the classification of cooksoni, johnstoni and albojubatus need further thought. My current view is that cooksoni and johnstoni are disjunct subspecies of taurinus, and that albojubatus is a species in its own right.

The population at Gorongosa in central Mozambique, which was also disjunct and is now extinct, possibly qualified as a subspecies in its own right, but this is now probably unknowable.

The species-distinction between mearnsi and albojubatus may seem unlikely because both straddle the border between Kenya and Tanzania, both have pale beards, and they approach each other closely in the Ngorongoro/Manyara area. However, they are more different from each other than most naturalists realise, and there are several other bovids that have treated the Great Rift as a geographical border, despite the relatively trivial topographic barriers involved.

I have been emboldened to formulate my own views on the classification of Connochaetes, since realising that subspecies mattosi of species taurinus remained unnoticed by all the experts in the field, including even Estes, who really is a 'guru of gnu'. If something as obvious as the distinction between mattosi and nominate taurinus has 'hidden in plain sight' all these years, how much do we really need to heed the current consensus on species/subspecies in Connochaetes?

So, species taurinus does show the kind of intraspecific variation you've alluded to, in the form of three subspecies distinct enough that they can easily be recognised in photos, plus a narrower distinction between cooksoni and johnstoni. I see mearnsi and albojubatus as additional spp., making the total tally within the genus four spp. (gnou, taurinus, albojubatus, and mearnsi) and four sspp. within taurinus (taurinus, mattosi, cooksoni, and johnstoni).

Your further thoughts?

Αναρτήθηκε από milewski πάνω από 1 χρόνo πριν

@milewski thanks for your thorough response.
As with all taxonomic work, I suppose genetic analysis will have the final say. I'm still skeptical, and note some near overlaps of mearnsi and albojubatus in Kenya's central & southern rift - Mara, east through the loitas to Narosura and up to Naivasha (mearnsi) and Shompole (literally 600m below Narosura) through to Suswa (albojubatus) - and very little detectable difference in vocalisation (in my personal experience).
I have less experience with the other subspecies, so I don't dwell on them

Αναρτήθηκε από zarek πάνω από 1 χρόνo πριν

@zarek

Many thanks for the information that mearnsi and albojubatus have similar vocalisations. I lived on a game ranch on the Athi-Kapiti plains, for years, in the habitat of albojubatus, but I do not recall ever hearing it vocalise. So, despite having intense experience of albojubatus, I have been completely ignorant of how it sounds.

Here is a prediction: that one needs go only as far as Mikumi National Park to hear the nasal 'kwoing' of taurinus (in the form of ssp. johnstoni).

Also, thanks for the interesting fact that the two forms, mearnsi and albojubatus, approach each other so closely in the Narosura-Shompole area of the Great Rift.

The wildebeest at Shompole Conservancy (please scroll in https://mymodernmet.com/shompole-hide-will-burrard-lucas/) looks typical for albojubatus.

However, are you aware that the population of mearnsi at Naivasha has been introduced by human agency, considerably beyond its natural range?

Αναρτήθηκε από milewski πάνω από 1 χρόνo πριν

Connochaetes taurinus cooksoni adult female:

scroll to 4th photo in https://www.edwardselfephotosafaris.com/september-luangwa-photo-safari-with

Αναρτήθηκε από milewski πάνω από 1 χρόνo πριν

Thanks @milewski, I wasn't aware of the human interference involved with the C. t. mearnsi around Naivasha. Interesting discussion on those two records. Will look further into that intoduction in 1985

Αναρτήθηκε από zarek πάνω από 1 χρόνo πριν

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