Across:
1. Unusual animal in horse captivated by layer (6)
5. Where animals live a little in headwear (8)
9. Primate keeping human leader and king of the jungle as far from the sun as it can get (8)
10. Small animal broke leg in primitive type of trap (6)
11. Live with a right animal (4)
12. Relevance of currency containing saltpetre brought to the west (10)
14,8dn,23ac. Unusual animal pal of 13 22 in town ... I hope he is reformed (6 3 4)
16. Ruder Mr Rude becomes less rude? (7)
18. I'd turned generous clue for "Enigma" into "Bucolic" (7)
20. A trick embracing love to get in the mood (6)
21. Some high tech weaponry and garb men eye off (6 4)
23. see 14
24. Religious leader beginning to twitch, being a jumpy animal (6)
26. "Gloamin'" brought back by tenth gill, woozily (3 5)
27. He's a kind sort, although he may look mean (8)
28. Unusual animal with eye damaged by mineral (6)
Down:
2. Little monster turned noisier when pierced by cathead's roughness (11)
3. Bonnie writer some agree rocked (5)
4. Green woodpecker's discomfort treated with whiskey according to Spooner (4-3)
5. U.N. dread wandering crew in 'hood where 23 across 11 lives (7 4 4)
6. After trimming perm, sit P.A. back up for induction (7)
7. Mad goat beginning to eat robes (5)
8. see 14 across
13. Wren perhaps and gopher beheaded by religious leader? (11)
15. Any confusion? No! (3)
17. One who attends to horse naked, who can be a jumpy animal (3)
19. This may be received as infant formula, yet teething maintained (7)
20. Unusual animal beginning to emulate writer (1. 1. 5)
22. Hood perhaps of bird? (5)
or  22. see 13
23. "Dear Prudence" really starts very cold (5)
25. Reserves essentially providing refuge for animals (3)
Solution:
TIGGER=HABITATS|
=M=R=A=U=A=O=H=|
APHELION=PIGLET|
=R=E=N=D=T=A===|
BEAR=PERTINENCE|
=C===I=E=S===H=|
WINNIE=DEMURER=|
=S=A===A===O=I=|
=IDYLLIC=AROUSE|
=O===A=R=A===T=|
ENERGYBEAM=POOH|
===O=E=W=I=R=P=|
RABBIT=OWLLIGHT|
=R=I=T=O=N=C=E=|
SKINHEAD=EEYORE|
Name: 924 - Unusual Animals
Author: by BenDR

Annos-Across:
1. GG in TIER
5. ( A BIT ) in HATS
9. AP(H)E + LION
10. *LEG in PIT
11. BE + A + R
12. rev( NITRE ) in PENCE   (nitre=saltpetre)
14,8dn,23ac. *( IN TOWN I HOPE HE )
16. *( RUDER MR )
18. ID + rev( CILLY )
20. A + ( O in RUSE )
21. *( GARB MEN EYE )
24. RABBI + T
26. rev tel (ten)TH GILL, WO(ozily) <
27. *( HE'S A KIND )
28. *EYE + ORE
Annos-Down:
2. IMP + rev( NOISI(C)ER )
3. tel (a)GREE R(ocked)
4. sp( PAIN RYE )
5. ( *( UN DREAD ) + CREW ) in HOOD
6. rev tel (per)M SIT P.A. B(ack) <
7. *GOAT + E(at)
13. CHRIST + (g)OPHER
15. *ANY
17. (g)ROO(m)
19. tel (formu)LA YET TE(ething)
20. *ANIMAL + E
22. dd
23. P R + ICY
25. (p)ARK(s)
Defs-Across:
1. Unusual animal
5. Where animals live
9. as far from the sun as it can get
10. Small animal
11. animal
12. Relevance
14,8dn,23ac. Unusual animal pal of 13 22
16. less rude?
18. Bucolic
20. to get in the mood
21. Some high tech weaponry
24. a jumpy animal
26. Gloamin'
27. he may look mean
28. Unusual animal
Defs-Down:
2. roughness
3. Bonnie writer
4. Green woodpecker
5. where 23 across 11 lives
6. induction
7. robes
13. Wren perhaps
15. No
17. who can be a jumpy animal
19. This may be received as infant
20. writer
22. Hood perhaps
22. bird
23. Dear
25. animals