A puzzling nature walk

While wandering through the forest
Taking lots of snaps
I found a mossy clearing
Where my pup could take a nap

I glanced around the bushes
I heard a rustling sound
And there I spied a crumpled note
Lying on the ground:

T IXY BS T ZXWI ZKX SUFQS IWXZUPS

I’m not sure what to make of it, can you find the answer?

(I’m a long time lurker on this forum and this is my first puzzle; it is written by myself. I had a look for a ‘first time poster’ guide but couldn’t find one, please let me know if there are any issues with how I’ve composed this post.)

HINT 1: congratulations to Supersonic for the solve, but why did I pick that cipher?

How does the story in the poem link to the cipher rather than the answer?

HINT 2:

Up jumped my little canine friend
He dashed over to see
A bark, a snap, he ran back over
In his mouth - a key!

HINT 3: this is the final hint, if it isn't solved by tomorrow I'll post the rest of the answer.

Oh, what a strange note to find!
I wanted to know better
I took a seat, pulled out a pen
And wrote down ALL the...

• I tried it as a cryptogram and here is what I got: rot13(H SBT VF H JBYS JUB FRNZF SYBJREF) – Duck Sep 8 '19 at 15:29
• Oops! I was so close :) I don't know a wolf who rot13(frnzf sybjref), though. – Duck Sep 8 '19 at 18:03

This is a

Cryptogram

which stands for

"A FOX IS A WOLF WHO SENDS FLOWERS" which is a quote of Ruth Brown.

Method:

This looked like a cryptogram because of the two Ts which could correspond to As. So I mapped them as such and looked at BS, which could correspond to AS or IS. I chose to work IS first because it looked more plausible and I got lucky there :)
ZKX looked like it would correspond to WHO which would work with IS A, so I tried it as I couldn't think any others that would work off the top of my head, and got lucky again :)
Now with all the substitutions we have:
A _O_ IS A WO__ WHO S___S __OW__S
I know and like that quote, so this were enough to see that it could work, and trying it out I found out that it does work! The reason I solved this quickly is that I got lucky twice :)

• So quick! How did you find the answer? – Tonks Sep 8 '19 at 15:49
• @Tonks I will update the answer with my method, thank you for confirming! :) – user47134 Sep 8 '19 at 15:57
• Your method is great, but there’s a bonus thing to solve regarding the cipher I used... I’ll add a hint to the question! – Tonks Sep 8 '19 at 16:54
• I've taken the best answer tick away for now to encourage more people to try out the second half of this, if that's alright? I'm still not sure on the protocol here haha. – Tonks Sep 9 '19 at 11:39
• @Tonks I'm completely okay with that! :) – user47134 Sep 9 '19 at 11:40

In the story there is

a lazy dog (must take a nap)

a fox

So the key to the cipher is

"The quick brown fox jumps over the lazy dog"
(a sentence with every letter in it)

Starting with the whole alphabet and writing every first appearance of a new letter beneath:
$$\begin{smallmatrix}A & B & C & D & E & F & G & H & I & J & K & L & M & N & O & P & Q & R & S & T & U & V & W & X & Y & Z\\T & h & e & Q & U & I & c & K & B & r & o & W & n & F & X & j & m & P & S & v & l & a & Z & Y & d & g\end{smallmatrix}$$
We get the substitutions needed to decode the cipher.
(The Uppercase letters are actually used letters in the cipher).

• Correct, well done! I'm going to award Supersonic the best answer because the main solve was the decryption which helped you find the key, but I'm so glad you got this part! – Tonks Sep 11 '19 at 7:50