Help! Franciscana or Cotero Dolphins?
Help! I have have been agonising over photos of Franciscana and Cotero Dolphins (Giuanan Dolphins) trying to turn at least one of the animals I saw in Brazil last week into a Franciscana. I would love some opinions.
I was in the Paranagua Estuary south of Sao Paulo. There are – or at least were n 2008 – Franciscanas here. Back in 2008 the species was not uncommon exactly where I was. There are also Guianan Dolphins. And the two species can look remarkably similar. Adult Franciscanas have much longer beaks than Coteros, but in younger animals there appears to be no difference. Fransciscanas also have more club shaped pectoral fins, but getting a view of those is tricky. The other diagnostic feature is the dorsal fin: it is quite triangular in a Cotero and much more rounded/flat-topped in a Franciscana. But of course there are variations.
The animal in the first two photos of this series below seems to have a dorsal fin that is more like a Franciscana’s than a Cotero’s, but I am not convinced. It also seems to lack the darker dorsal cape that the other dolphins we saw had (not sure if that is any use though as a diagnostic). But I would LOVE other more expert opinions. Some reference shots of Fransicana dorsal fins from the same waters are in this paper.
Possible Fransicana? Longish beak, rounded dorsal fin and seems somewhat paler on the back than the animals below.
Guiana Dolphins (Cotero) I think – with a more falcate, triangular dorsal fin
10 Comments
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Vladimir Dinets
From a beach on the southern outskirts of Mar del Plata, back in 1995. The beach also had southern tuco-tucos. You can easily organize a boat trip there, or just go out on a hotel sunset cruise, but I don’t know how regular are the dolphins. I would simply email a couple beachfront hotels and ask.
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Jon Hall
Will do! Pygmy Right Whales are extremely hard but they occasionally turn up in weird places. There was one in Portland Harbour Australia 20 years ago that hung around for months I believe (I didn’t see it…) and there was another in Capetown Harbour a year or two back. So keep you bag packed and your passport uptodate 🙂 Tuco Tucos are relatively easy I think in many places (as easy as Pocket Gophers are here at least and this from someone who has only seen 1 Pocket Gopher in 6 years here!)
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machunter
I do get the impressions that southern Oz will be our best bet for pygmy right whales and as we phase into retirement we plan to spend much time there (starting next Nov) to avoid the dark days of the northern solstice. Is there a website to monitor besides this one for rare whales hanging around? …mac
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Vladimir Dinets
PRWs are sometimes seen near the E entrance of Beagle Channel. Lots of cruise ship going to/from the Antarctic pass through there, but even the official naturalist guides often can’t tell the difference between this species and Antarctic minke, so it’s often overlooked. Look for the white edge of the lower lip and widely spaced flukeprints.
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JMichel Bompar
Hi Jon,
despite “your” dolphins don’t show the (sometimes very subtle) eye-to-flipper dark line, all seem to be Sotalia because of 1-) the pointed flippers of the jumping dolphin (rounded in Pontopora) 2-) the short beak 3-) the curved mouth line.
Amitiés JMichel