Identification tips for IDs

I personally find it to be very fascinating when someone explains how they figured out what species a sighting was with different identification tactics after placing an ID on a species, and I wish it was a bit more prevalent as it could help newer users to the app. Just wanted to put it out there as it’s been a thought I’ve had for a while, this was not meant to be a complaint.

Perhaps some means of spotting differences between similar species could be shared on this forum. It would be very interesting to see the numerous ways of identifying different species from one another.


I know some people do this regularly, but it can also take a lot of time to do well. For IDers, it’s often a choice between explaining a few IDs with comments or actually making many more ID but not including comments. I think most IDers tend to go for the making more IDs option (though not all). I think it’s great to ask how people made IDs in a comment though! When IDers know that someone cares and is actually going to read the explanation, I think many are happy to share their expertise.

There are also some really valuable guides that users have written up (either on iNat or in other venues) so they can point people towards them. I often see these posted in users profiles. One guide I often point people toward is this one for the common anoles of Miami, which is pretty easy to use with lots of pics, since I really focus on IDing these species.


I love the way you explained this regarding the time it can take, yet also how using comments as ways of asking naturalists how they found out an ID, as well as using guides. Thanks for the advice.

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There’re many topics dedicated to ids and help with ids, it’s practically impossible to write down an explanation every time, but users should feel ok to ask questions, now it would be helpful if you could narrow down the group you’d like to see advices about as there’re so many possibilities!


I was mainly thinking of fish and arthropods, however I feel this would be helpful for many other groups of animals as well.

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When I had wrote the part about naturalists sharing how they identify differences between similar species, I just wanted to see what interesting replies I could get and that me and other naturalists could read and note down for future IDs.

I recall there is an ID feature in the AI for Similar Species. I’ve wished the AI could evolve to include difference between for such similar species.


I know this comment won’t reach the right people, but it would be nice if when identifiers do take the time to explain their ID, they think about making it a learning experience for the observer. Specifically, instead of saying “I went by the color and shape of the leaves” or “the number of eyes” or whatever, say “the leaves have a blue cast and are too narrow to be x” or “it has six eyes rather than eight.” People really appreciate that – I know because they add a “thank you” comment.


I (very) occasionally write about ID issues in my journal in more detail. Mostly it’s just to keep a record for myself after I’ve sat down with a bunch of resources to figure out how to tell two similar species apart. However, these could also be used to link to when doing IDs and sometimes I hope to draft others into identifying often misidentified similar species just shy of being included in the next computer vision model.


It helps to pick a group like a genus and a location and first review Research Grade observations. Look to see if identifiers left an ID basis or discussed ID features. If they didn’t you can ask them what their ID basis was.


Some of the comments I’ve seen on fish would disappoint you; they explain bumping an ID back to genus because two similar-looking species can only be distinguished by counting fin rays and scale rows.

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I’m somewhat new to ID’ing things but I’ve learned a handful of things I wouldn’t mind sharing since we’re on the topic. It’s a good idea to learn large groups of taxa like families, then go from there. If you know that something is in a certain family, you can look for what genera or species are common in the area that it was spotted in, then go from there. I’ve done a fair bit of that recently, mostly with various lepidopterans. Here are a few pointers:

- Geometer Moths (Geometridae) -



  • Usually cryptic coloring (brown, grey, white, etc.) though there are exceptions such as the emerald moths
  • Wavy patterns, may have numerous waves, just one very prominent one and anywhere in-between
  • Larvae are “Inchworms”
  • Average, medium size
  • Resting posture has the wings open and spread, usually with hindwings visible

- Saturniid Moths (Saturniidae) -


  • May be cryptic or brightly colored
  • Often (but not always!) have eye-spots on wings
  • Large, heavy bodies
  • Feathered antennae which are bushier in males than in females
  • Vary in size, though most very large moths are in this family
  • Resting posture has the wings open, with hindwings visible but forewings often slightly overlapping them

- Sphinx Moths (Sphingidae) –


  • May be cryptic or brightly colored
  • Patterns may be simple or dizzyingly complex
  • Hindwings may have eyespots
  • Flies with loud and very rapid wingbeats, a few species can hover in place during flight
  • Most species are nocturnal but a few are on-wing during daylight hours
  • Medium-large
  • Resting posture has the triangular forewings obscuring the hindwings, creating an unmistakable “W” silhouette

- Skipper butterflies (Hesperiidae) -


  • Mostly shades of brown or grey
  • Larger bodies than most other butterflies, which are quite slender
  • Antennae have a hook-like shape on the end
  • Very small
  • Quick, darting flight pattern
  • Resting posture has the wings mostly or entirely closed, exposing the ventral side
  • Many species in this family cannot be distinguished by photo or in the field even by experts!

- Gossamer-winged butterflies (Lycaenidae) -



  • Brightly colored and sometimes metallic, most often blue or orange
  • Ventral sides are spotted and more drab than dorsal sides, usually grey with a touch of orange
  • Females of the Polyommatinae (“Blues”) subfamily are primarily brown but may still have small amounts of blue, distinguishing them from coppers
  • Brown individuals can be distinguished from skippers by the latter’s unique antennae shape
  • Very small
  • Resting posture has wings closed, exposing the ventral side

I could probably go on but this is already a pretty long comment and I would hate to spam or completely de-rail the thread so I’ll stop here. Hope this was interesting for you! :)


well first is that don’t mess things up by idying what AI says because sometimes AI also mess up, and second if someone disagrees your id ask “why you disagreed?”, this will increase your knowledge or just change your perspective abut that observation, if you are new to idying try to id little observation, and also write why you think it is that(only of those ids whichyou are absolutely sure) and tag the expert in that field, don’t tag one person more than 2 times because he is also a person and he also has something else to do.
id slowly and you will learn different ways to id. Try seeing some research grade observation of ur particular intrest and try to see its features and learn about them, don’t be down when u mess up id, just be humble and see what u have id is correct or not.

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Nailed it.


I completely agree. If the IDer doesn’t respond, the observer can always ask another user who has knowledge of both species.


I have a few copy-pasted messages which I use for correcting IDs that often get mixed up (much easier when you’re batch-correcting a whole bunch of observations at a time!).

For example, I often use “This is not a spider, but a harvestman - another type of arachnid”. I think this at least acts as a reminder to the observer that there are other types of arachnids beside spiders, and if they’re then curious about what exactly a harvestman is they can go research this some more. Even a simple explanation about why it’s not something is better as an observer than just being presented with “X disagrees this is a spider”, which can be confusing if you have it in your head that 8 legs = spider.

There’s some extra information I sometimes include on how to differentiate harvestmen and spiders RE their round body shape (not split into a separate “head” and abdomen like spiders) and the longer second pair of legs in relation to the first, but I don’t always include this mainly out of laziness :( I just need to remember to go add it to my copy-paste message list at some point!

If you give someone the tools to make accurate IDs for themselves, you reduce the chances that they’ll make the same mistake again in the future. That’s less work for everyone involved in the long-run, even though it takes slightly more time in the short-term (but barely any more time if you’re using standard messages which you can paste onto multiple observations!)


It takes two. Ask. And if someone explains to you - then pay that forward, by helping to ID the backlog (now that you can!)


I’ve done that! Thank you for providing some excellent resources!

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and more importantly most if not all Geometrid caterpillars have just one pair of abdominal prolegs, plus the anal pair.


Really recently I started to actually write down my ID process when I spend a bit of time trying to identify something new. It’s time consuming for sure, but I find it’s really helpful both for other people and for myself in the future when I’ve forgotten everything that I learnt. Previously I would spend ages on an ID and then not write much (or anything) down about how I got there, which I reckon is just a waste of time! That way after I get a name I can link back to it when I ID it for other people. (I’ve also collected them all together here)

In terms of identifying other people’s sightings, I agree that it’s often a toss up between adding comments or making lots of IDs. If someone asks me how I IDed something, I’m always more than happy to explain my reasoning. If I’m just going through making hundreds of IDs though, I tend to avoid comments unless it’s something unusual or someone has tagged me specifically