15 November 2024

Robinson’s Mouse Opossum – biofluorescence

I’m a neophyte mammal-watcher- fairly experienced birder, so I’m not sure how unusual this note is.  In July 2024 I spent several days at a lodge on the Napo River in Ecuador. During a night walk we found what appears to be a Robinson’s Mouse Opossum, which is apparently not that unusual for the area.  We were all pretty surprised, though to see it flouresce in bright pink under a black light.  I’ve been reading that recently some mammals have been found to glow under UV, but I haven’t seen this species listed as one of those.

 

 

                                     

 

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Post author

mikec
I’ve been actively interested in natural history for pretty much my whole life, with observations back to the late 1960s.  My primary interest has been birds, but that’s only because there are more of them and they’re easier to see and identify! But mammals, herps, insects are all on the radar for me.
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3 Comments

  • 16 November 2024
    Charles Foley

    That’s a fantastic record. I strongly suspect you and your friends are the first people to discover this about this species, for the simple reason that nobody has ever shone a UV light at the majority of mammal species. You should think about publishing a note about it.

    3
  • 4 December 2024
    Ben S

    Awesome observation! You’ve motivated me to purchase a UV light for my next trip to the Amazon.

    Mouse Opossums are, to my knowledge, currently impossible to identify to species level in the Ecuadorian Amazon as there are likely (many) undescribed taxa. It’s sometimes difficult to identify to genus level. I’d guess I’ve observed 10+ species of mouse opossums in Western Amazonia and I think I can identify only one to species level (and only because it was at higher elevations where diversity is lower): https://www.inaturalist.org/observations?taxon_id=846215&user_id=tremarctos. According to the current taxonomy the mouse opossums in Ecuador formerly considered M. robinsoni are now referred to as M. isthmica, and they are only known to occur on the west slope of the Andes: https://bioweb.bio/faunaweb/mammaliaweb/FichaEspecie/Marmosa%20isthmica

    • 6 December 2024
      mikec

      Thanks for the additional information, Ben. I had no idea that the taxonomy was so complicated. I’ll pass your details on to the guides in the area- I’m sure they are also not up on the current status!

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