Part 1 — Safe Introductions: A Step‑by‑Step Plan

1) Start Apart (Decompression Phase)

• New pet gets a quiet room/zone with their own bed, water, and bathroom setup.
• Resident pets keep routine access to the rest of the home.
• Swap scent first: trade blankets, toys, or use a soft cloth to rub cheeks/shoulders (cats) and share.

2) Positive Associations (No Contact Yet)

• Meal magic: feed on opposite sides of a closed door so “other‑pet smell = good things.”
• Calm soundtrack: soft voices, short visits; everyone gets treats for relaxed behavior.

3) Peek‑a‑Boo (Barrier Intros)

• Use a baby gate, door crack, or carrier view. Aim for short, boring sessions.
• Goal: quiet curiosity. End on neutral or positive notes; keep it brief.

4) Short, Supervised Meetings

• Dogs: on leash; neutral space if possible. Reward check‑ins with you.
• Cats: free in room with escape routes (vertical perches). No chasing allowed.
• Small pets/birds/reptiles: remain fully contained; visual only.

5) Expand Time & Territory Gradually

• Add minutes, then rooms. Keep resources duplicated (see Part 3).
• If tension rises, back up a step. Reps over heroics.

Pro tip: End every session while it’s still going well—so the last memory is “this is fine.”

Part 2 — Species‑Specific Playbooks

Dog ↔ Dog

• Parallel walk first (two handlers, few meters apart). Reward calm glances.
• Short sniff‑and‑go; no lingering stare‑downs. Leashes loose, tone light.
• Inside: remove high‑value toys at first; teach “place” or settle on beds.

Dog ↔ Cat

• Dog on leash; cat controls distance and escapes upward.
• Scent swaps → feed across door → gated visuals → brief room time.
• Interrupt fixations (soft name cue, treat scatter). Zero chasing, ever.

Cat ↔ Cat

• Scent swapping; room rotation (each cat explores the other’s space alone).
• Crack‑door peeks, then short supervised sessions. Several litter boxes (see Part 3).
• Add vertical territory (trees/shelves) to reduce crowding.

Predator ↔ Prey (birds / small mammals / reptiles / fish)

• Assume no face‑to‑face. Safety is architecture: solid enclosures, locked lids, away from paws and snouts.
• Birds: no aerosols/PTFE cookware; out‑of‑cage only in closed, pet‑free rooms.
• Fish: sturdy stand, secure lid, cords hidden; tanks out of pounce zones.
• Reptiles & small mammals: chew‑proof cables, latchable doors, quiet rooms.

Part 3 — Separate Essentials (Resource Peace Model)

Give every pet the basics, duplicated.

• Food & water: separate stations (ideally out of sight). Slow feeders for gulpers; raised bowls for large dogs if advised by your vet.
• Beds & hides: one per pet plus extra. Dogs: beds/crates in different rooms. Cats: add high perches and cozy caves.
• Litter boxes (cats): one per cat +1, in different locations, easy access, scooped daily.
• Toys: multiples of favorites; rotate to keep interest and reduce squabbles.
• Attention: 1:1 time with each pet—play, training, grooming—so no one feels replaced.

Part 4 — Reading the Room: Body Language 101

Early tension signs (intervene kindly):

• Dogs: still/stiff posture, hard stare, frozen tail, lip lift, low growl, “possession hover” over food/toys.
• Cats: tucked or twitching tail, ears sideways/back, pupils big, stillness before a swat, hiding/avoiding, urine marking. What to do:
• De‑escalate: calm voice, increase distance, redirect (treat scatter, name cue, toy toss).
• Reset: short break behind a gate/door, then try again later at an easier level.
• Never punish growls/hisses—they’re safety warnings. Thank them silently and give space.

Part 5 — Kids in Multi‑Pet Homes

• Teach the script: inside voices, slow hands, no chasing or hugging.
• The safe zone (crate, bed, perch, hide) is off‑limits to kids—always.
• Every interaction supervised for weeks, then gradually eased if all is calm.
• Assign gentle jobs: refresh water, measure kibble, 5‑minute play timer with wand toy (cats) or fetch (dogs)—with an adult present.

Part 6 — Keep the Peace (Long‑Term)

• Routines win: predictable meals, play, and sleep.
• Rotate enrichment: puzzle feeders, snuffle mats, foraging toys, scent games.
• Train tiny, daily: 3–5 minutes of cues or tricks builds focus and drains steam.
• Seasonal resets: new baby, move, holidays? Rewind to slower intros for a week.

Part 7 — When to Call in Reinforcements

Don’t wait for “World War Fur.” Seek help if you see:

• Repeated fights or injuries, escalating growls/hisses, resource guarding that won’t fade.
• Extreme stress (hiding all day, shutdown, persistent pacing/panting).
• Any bite/scratch that breaks skin.

Who to call:

• Veterinarian (rule out pain/medical causes; discuss meds if needed).
• Certified trainer (reward‑based; no aversives).
• Veterinary behaviorist/behavior consultant for complex cases.