If you Google "animal sounds," Google presents an array of such sound effects. Inspecting the element with a broser allows me to download the effect. There is no licensing information available. May I use these sounds in a commercial project?
Interesting that they don't give a source and also don't link to anywhere (such as Wikimedia commons). So I assume that content is google's own.
So generally speaking: No, when no license is provided, that means you can't use whatever it is in a project of yours (whether commercially or not), because the "default", when nothing is specified, is that no license is given. So unless you find a license that grants you a permission on google's own content, these sounds can't be used freely.
You can "use" Google's link to their sounds, e,g, a scorpion sound, but you cannot copy the content without their permission. It is not obvious whether you have been given permission to copy (and if so, with what limitations). You can read the developer's TOS, which is implicated in using their "Sound Library". The burden would be on you to prove that you have permission to copy their content, so if you find a license that allows you to copy, you also would have to prove that the permission applies applies to the particular file, which you almost certainly cannot do.
Probably, individually at least.
When I google "animal sounds" I get two sorts of results:
- Creative works created by humans that involve animal sounds (eg. youtube video). These are clearly protected by copyright and you cannot use them without permission. I assume you do not mean these.
- Recordings of real animals making sounds (eg. from SeaWorld). I assume this is the sort of thing you mean.
Whether these recording are protected by copyright is not a simple question.
If the recording was made in an automated fashion one could suppose it would be held equivalent to a photograph of an animal taken by an automated camera. In the Monkey selfie copyright dispute the United States Copyright Office stated that works created by a non-human, such as a photograph taken by a monkey, are not copyrightable. The case has been argued in multiple courts, and it seems that the legal process ended when the person who set up the camera ran out of money (which google is unlikely to do), so this cannot be considered definitive.
Collections of animal sounds are likely to involve creative decisions involving which to include. This would mean that the collection is protected by copyright, even if the individual sound files are not.