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22 November 2011

Otter or not otter ?




















Old track (left) and more recent one (right)

Last week I saw along the banks of the Red River some footprints which, I am almost certain, belong to an otter. Guess where it was… At Vinh Tuy !

I would like to have your opinion. I am not a specialist of mammals, but I have spotted at few occasions footprints of otters in France.
Yesterday at noon, I walked again along the river banks in search of new footprints. I found a track, beginning near the water and ending on the dry sand where I lost it.
I think it is an otter because of :


-first, the width of the feet : 5,5-6 cm (pen lenght : 14cm). For comparaison, a smaller mustelid of the size of the mink = 2,5cm.
- the five pointed toes (the smaller, inner toe, sometimes not visible), with claw marks and sometimes a clear imprint of the webbing .
I also met a fisherman (one of those who live 24h/24 on their small sampans with all their family, along the sandbars of the river) and asked him if he had already seen otters there (at that time I didn’t know the vietnamese word for otter, so I described it).
He understood immediately and answered : “con rái cá ? bây giờ hiếm lắm, chỉ thỉnh thoảng mới gặp thôi !” (“the otter ? rare now, I encountered one from time to time only !”).

There are 4 species of otter in Vietnam. The Eurasian Otter has been recorded in 7 provinces (North and Centre), among them Hoa Binh and Lai Chau (link here).

Cheers,
Sebastien

10 comments:

  1. Hi Sebastien

    You do it again! They certainly look like Otter footprints to me / us. I am talking to a North American hunter right now, and he says that one Otter indicator is a tail drag. Did you see any of these, while you were tracking it?

    Wayne

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  2. Hi Wayne,I didn't notice any tail drag; but i am not sure that the tail can always leave imprint (maybe on soft mud, which was not the case there). But on the snow, that is certain ! Sebastien

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  3. Hello Sebastian,

    I'm not convinced that these prints belong to an otter. They look too compact to me, with the toes lying too close to the pad and bunched up. The size and shape of the print, and the layout of the digits would suggest a palm civet. Yellow throated marten is another possibility, though I'm more inclined at this stage to think common palm/masked palm civet.

    However, identifying prints even to a taxon can be bloody hard! So this is just my opinion. Would you be able to send me the original photographs so that I can have a better look? I also have some documents on small carnivore tracks for you to gaze your beady eye over if you're interested.

    Daniel

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  4. Hi Daniel, thanks for posting !
    Do you think that Palm civets and martens can leave footprints of 5,5cm width ?

    Seabstien

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  5. Hello,

    Where on the print were you taking the measurement from? The widest point? Or the bottom of the pad?

    Daniel

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  6. Hi Daniel,

    It is the width across the toes. You can try by yourself, the pen length is 14 cm.
    And you Wayne, what your North American trappers friends think about this tricky question ?

    Sebastien

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  7. Daniel-oi, I have to disagree (even though I am not a North American trapper :-)) - this doesn't look right for a civet, even the larger ones...
    I might be wrong but it really does look like Otter to me. Only other animal I could think of with a very similar footprint would be the mentioned Y-t Marten?
    Oh Lord, please give us some light!
    Cheers,
    Falk

    Oh btw, if it turns out the tracks are too small for Eurasian, what about Small-clawed Otter?

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  8. Hi again

    the key for an otter is that it has a big heavy tail. It only holds it up for so long before dragging it. If you follow Otter tracks long enough, you always see the tail drag. They say it is obvious when you are looking for it. Given how deep the prints are in places, this should be visible (when you find it) in the mud... (or even on dry sand).

    Wayne

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  9. There are claw marks, which rules out small clawed otter. hmmm it is a bit too wide for a palm civet, I was looking mainly at the length before. I'm going to be annoying and play devil's advocate on this, one has to be extremely cautious when identifying tracks or other animal signs. I don't think YTM can be ruled out based on these photographs, though it would have to be a BIG YTM.

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  10. I think we can also rule out YTM, for the simple reason : there is no suitable habitat for it there ! The only "wooded" area for some distance is a 3-4 ha plantation of lytchees ! Ok, the trees are old and tall, but it is a bit hard to imagine some martens living there.
    Sebastien

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