The sounds the squirrel makes correspond to the tones that the terminals make when you use the POTS (Plain Old Telephone Service) in the US:
It may also be the case that "squirrelphone" is a reference to the popular web-mail software SquirrelMail.
The title text takes the joke further by showing the squirrel possesses another phone feature: that cordless phones need to recharge frequently, either by setting them at their cradles or by connecting them to a charger, in the case of mobile phones. When they sense the battery is low, they emit a beeping noise every few minutes. In this case, the stump is the squirrel's cradle. However, the reason that cordless phones beep when they are getting low on battery is in order to alert humans to move them to the charging cradle because the phones cannot move themselves. On the other hand, squirrels can move on their own without needing humans to pick them up, so the squirrel likely only does it in order to trick people into picking it up, which further suggests that it is a vampire squirrel.
Could it be a reference to this? http://web.media.mit.edu/~stefanm/phd/cellularsquirrel/ 184.108.40.206 (talk) (please sign your comments with ~~~~)
- I think it might be a reference to this: ‘Vampire squirrel’ caught on camera for the first time ever – Washington Post. --220.127.116.11 07:35, 16 September 2015 (UTC)
- agreed:  18.104.22.168 10:25, 16 September 2015 (UTC)
What about the old "Bananaphone" pun? 22.214.171.124 (talk) (please sign your comments with ~~~~)
Sometimes I wonder if the joke is to make ExplainXKCD squirm. 126.96.36.199 (talk) (please sign your comments with ~~~~)
^ Not really. Those like me who used SquirrelMail had a laugh. Mostly every XKCD joke is incomprehensible to people not familiar with the subject of the joke. 188.8.131.52 (talk) (please sign your comments with ~~~~)
"a living squirrel being not an appropiate creature to mantain a phone call. "... well, duh. Everyone knows that a squid would make MUCH more sense! 184.108.40.206 05:16, 16 September 2015 (UTC)
- A puppy... www.youtube.com/watch?v=e0tiNwOpZ68 220.127.116.11 14:11, 16 September 2015 (UTC)
- I doubt this is supposed to be about SquirrelMail; it's much more likely to just be "Bananaphone" with a squirrel. 18.104.22.168 05:33, 16 September 2015 (UTC)
- Maybe a _dead_ squirrel would work better. At least it wouldn't bite... Elektrizikekswerk (talk) 08:16, 16 September 2015 (UTC)
"chomp" is also a command on unixoid operating systems that removes characters which carry no information (leading, trailing white spaces, newlines etc) from strings. Seems like the squirrelphone removed every bit of non-information, essentially cutting the call to nothing. 22.214.171.124 07:10, 16 September 2015 (UTC)
Whoever put that [needs citation] in there deserves a medal XD Apbarratt (talk) 08:34, 16 September 2015 (UTC)
Summary of POTS should be present tense - POTS is still active.
126.96.36.199 16:42, 16 September 2015 (UTC)
The tone played at the end is likely a howler tone, not fast busy.
https://en.wikipedia.org/wiki/Off-hook_tone -- Trenin (talk) (please sign your comments with ~~~~)
Do we really need an explanation of every noise landline phones make? Only two really apply here, ringing and howling. Since even cellphones have ringtones, I don't think ringing would need to be explained in the detail that it is, just something like "These phones would make a series of rings on receiving a call (as shown in the first panel) and would automatically stop ringing and answer when picked up."
I must admit I'm young enough that my first impulse for a squirrelphone beeping was "Oh, it must be one of those wireless home phone recievers and it's low on battery." I suppose squirrelphones must still be wired, though, though it doesn't look like it. 188.8.131.52 17:39, 16 September 2015 (UTC)
- Seems like we do need the explanation for the ring tones. Sine this is a real squirrel imitating a phone, it is of course not wired. It just pretends making the appropriate sounds. --Kynde (talk) 19:38, 16 September 2015 (UTC)
How do we know it's not a phone pretending to be a squirrel? Mikemk (talk) 23:55, 16 September 2015 (UTC)
What if the squirrel swallowed a phone? Like in Jurassic Park, when the spinosaurus swallows the satellite phone? 184.108.40.206 (talk) (please sign your comments with ~~~~)
- I think this is part of the joke. The way it is drawn shows the noise coming from the squirrel's abdomen not its mouth. It's not a squirrel pretending to be anything. The squirrel was probably just as surprised to be picked up and spoken into as Cueball was to be bitten by a ringing squirrel! --R0hrshach (talk) 16:06, 17 September 2015 (UTC):By that logic, all most characters in XKCD appear to talk out of their foreheads. Apbarratt (talk) 09:24, 18 September 2015 (UTC)
Just to let you know, there is nothing currently up on the wiki page that explains this comic. 220.127.116.11 (talk) (please sign your comments with ~~~~)
This whole page is dumb as hell. You guys overexplain everything. Not every joke requires or benefits from a multiple-paragraph explanation and a bunch of imagined allusions. This comic in particular should be a lesson that sometimes you guys need to take a day off on this site. And by the way, the "citation needed" joke has become a cliche.18.104.22.168 05:16, 17 September 2015 (UTC)
- You don’t have to read it – there are many other site on the net ;-). --DaB. (talk) 13:20, 17 September 2015 (UTC)
- They are correct though in this instance and many others. Often times when someone doesn't "get the joke" they still blather on in the explanation and it ends up sounding obtuse and contrived. I like to follow Albert Einstein's rule of thumb, "If you can't explain it simply, you don't understand it well enough". --R0hrshach (talk) 16:06, 17 September 2015 (UTC)
- Your whole commentary could be summarized by a link to 915, and I agree with you, except for the "citation needed" part. It seems to be a running joke on Randall's blog (blag) posts. I used to dislike it before I knew that. Now, I just tolerate it. Also, the explanation for the title text was completely missing, so I added one. Feel free to improve it, everyone. 22.214.171.124 03:27, 26 January 2016 (UTC)
Wait, seriously the POTS description is written in the past tense, as if it were something people were not used to anymore. Ringing landline telephones are not yet a thing belonging to history museums (although rotary dial ones almost belong there.) Ralfoide (talk) 14:21, 17 September 2015 (UTC)
This youtube video ("Animal Phone") seems to have some similarity in the content: https://www.youtube.com/watch?v=cMNW51-RmwU 126.96.36.199 14:30, 17 September 2015 (UTC)
I think the joke is that despite the absurdity of the situation, a squirrel ringing like a phone, Cueball just "goes with it" and picks up the telephone expecting it to work despite common sense telling him that however improbable the situation or why it is ringing it is still a squirrel. In the third panel, nature takes over and the squirrel does what it realistically would do. This leaves Cueball confused. If the squirrel was just a squirrel then why was it ringing like a phone? And if the squirrel was ringing like a phone then why did it bite him like a squirrel? It's a bit of the ol' Looney Tunes logic when Wylie Coyote would paint a tunnel in the side of a butte and the Road Runner would successfully use said tunnel entrance while for Wylie it would go back to being just a painting on the butte. I think we all have analogous life experiences. --R0hrshach (talk) 16:17, 17 September 2015 (UTC)
Alternative explanation: it's a squirrel which is more or less carrying out the function of a telephone. The message, from an unknown caller, who hangs up after delivering it, is a vicious bite. Stevage (talk) 11:25, 21 September 2015 (UTC)
Just a couple years ago I heard the unmistakable sound of a Nintendo Game Boy. It was a bird! 188.8.131.52 (talk) (please sign your comments with ~~~~)
184.108.40.206 16:47, 14 February 2020 (UTC) Could it be a Jojo reference to Diavalo who makes phone calls with his younger version of himself through various objects?
^ doubtful, especially since this comic was made before the anime for that part existed. --220.127.116.11 03:20, 10 November 2020 (UTC)