diff --git a/src/app.d.ts b/src/app.d.ts
index 039bbe1..44ed404 100755
--- a/src/app.d.ts
+++ b/src/app.d.ts
@@ -10,7 +10,9 @@ declare global {
 			session: typeof import('$lib/server/auth').auth.$Infer.Session.session | null;
 		}
 		// interface PageData {}
-		// interface PageState {}
+		interface PageState {
+			animal?: import('$lib/animaldex/AnimalDetails.svelte').AnimalDetail;
+		}
 		// interface Platform {}
 	}
 }
diff --git a/src/lib/animaldex/AnimalDetails.svelte b/src/lib/animaldex/AnimalDetails.svelte
new file mode 100644
index 0000000..be989ce
--- /dev/null
+++ b/src/lib/animaldex/AnimalDetails.svelte
@@ -0,0 +1,139 @@
+<script lang="ts" module>
+	export interface AnimalDetail {
+		id: number;
+		species: string;
+		breed: string | null;
+		animalName: string | null;
+		description: string | null;
+		sightings: {
+			id: number;
+			seenAt: string;
+			reporterName: string | null;
+			lat: number;
+			lng: number;
+			photos: { id: number; url: string }[];
+		}[];
+	}
+</script>
+
+<script lang="ts">
+	import { resolve } from '$app/paths';
+	import ArrowRight from 'lucide-svelte/icons/arrow-right';
+	import PawPrint from 'lucide-svelte/icons/paw-print';
+
+	let { animal }: { animal: AnimalDetail } = $props();
+
+	const title = $derived(animal.animalName || animal.species);
+	const allPhotos = $derived(animal.sightings.flatMap((s) => s.photos));
+	let activePhotoId = $state<number | null>(null);
+	const activePhoto = $derived(allPhotos.find((p) => p.id === activePhotoId) ?? allPhotos[0]);
+	const firstSeen = $derived(animal.sightings.at(-1)?.seenAt);
+	const lastSeen = $derived(animal.sightings[0]?.seenAt);
+
+	function formatDate(value: string) {
+		return new Date(value).toLocaleDateString('nl-NL', {
+			day: 'numeric',
+			month: 'short',
+			year: 'numeric'
+		});
+	}
+</script>
+
+<div class="grid gap-8 lg:grid-cols-[minmax(0,3fr)_minmax(0,2fr)]">
+	<div>
+		<div class="aspect-[4/3] overflow-hidden rounded bg-[var(--site-surface)]">
+			{#if activePhoto}
+				<img src={activePhoto.url} alt={title} class="h-full w-full object-cover" />
+			{:else}
+				<div class="flex h-full items-center justify-center text-[var(--site-muted)]">
+					<PawPrint size={64} aria-hidden="true" />
+				</div>
+			{/if}
+		</div>
+		{#if allPhotos.length > 1}
+			<ul class="mt-3 flex gap-2 overflow-x-auto pb-1" aria-label="Photos">
+				{#each allPhotos as photo (photo.id)}
+					<li class="shrink-0">
+						<button
+							type="button"
+							onclick={() => (activePhotoId = photo.id)}
+							aria-label="Show photo"
+							aria-pressed={photo.id === activePhoto?.id}
+							class="block h-16 w-16 overflow-hidden rounded border-2 {photo.id === activePhoto?.id
+								? 'border-[var(--site-text)]'
+								: 'border-transparent opacity-70 hover:opacity-100'}"
+						>
+							<img src={photo.url} alt="" class="h-full w-full object-cover" />
+						</button>
+					</li>
+				{/each}
+			</ul>
+		{/if}
+	</div>
+
+	<div>
+		<h2 class="text-3xl font-semibold tracking-tight sm:text-4xl">{title}</h2>
+		<p class="mt-2 text-lg text-[var(--site-muted)]">
+			{animal.species}{animal.breed ? ` · ${animal.breed}` : ''}
+		</p>
+
+		{#if animal.description}
+			<p class="mt-5 text-base whitespace-pre-line">{animal.description}</p>
+		{/if}
+
+		<dl class="mt-6 grid grid-cols-3 gap-4 border-y border-[var(--site-border)] py-4">
+			<div>
+				<dt class="text-sm text-[var(--site-muted)]">sightings</dt>
+				<dd class="text-xl font-semibold">{animal.sightings.length}</dd>
+			</div>
+			{#if firstSeen}
+				<div>
+					<dt class="text-sm text-[var(--site-muted)]">first seen</dt>
+					<dd class="text-base font-medium">{formatDate(firstSeen)}</dd>
+				</div>
+			{/if}
+			{#if lastSeen}
+				<div>
+					<dt class="text-sm text-[var(--site-muted)]">last seen</dt>
+					<dd class="text-base font-medium">{formatDate(lastSeen)}</dd>
+				</div>
+			{/if}
+		</dl>
+
+		<a
+			href={resolve(`/projects/animaldex/register?animalId=${animal.id}`)}
+			class="mt-6 inline-flex items-center gap-2 rounded bg-[var(--site-text)] px-4 py-2.5 text-base font-medium text-[var(--site-bg)]"
+		>
+			i saw this animal too <ArrowRight size={16} aria-hidden="true" />
+		</a>
+
+		<h3 class="mt-8 mb-2 text-lg font-semibold">sighting history</h3>
+		<ul class="divide-y divide-[var(--site-border)] border-t border-[var(--site-border)]">
+			{#each animal.sightings as s (s.id)}
+				<li class="flex items-center gap-3 py-3 text-base">
+					{#if s.photos[0]}
+						<button
+							type="button"
+							onclick={() => (activePhotoId = s.photos[0].id)}
+							aria-label="Show photo from {formatDate(s.seenAt)}"
+							class="h-10 w-10 shrink-0 overflow-hidden rounded"
+						>
+							<img src={s.photos[0].url} alt="" class="h-full w-full object-cover" />
+						</button>
+					{:else}
+						<span
+							class="flex h-10 w-10 shrink-0 items-center justify-center rounded bg-[var(--site-surface)] text-[var(--site-muted)]"
+							><PawPrint size={18} aria-hidden="true" /></span
+						>
+					{/if}
+					<span class="min-w-0">
+						<span class="block">{formatDate(s.seenAt)}</span>
+						{#if s.reporterName}<span class="block text-[var(--site-muted)]"
+								>by {s.reporterName}</span
+							>{/if}
+					</span>
+				</li>
+			{/each}
+		</ul>
+	</div>
+</div>
diff --git a/src/params/integer.ts b/src/params/integer.ts
new file mode 100644
index 0000000..7c6e0f8
--- /dev/null
+++ b/src/params/integer.ts
@@ -0,0 +1,3 @@
+import type { ParamMatcher } from '@sveltejs/kit';
+
+export const match: ParamMatcher = (param) => /^\d+$/.test(param);
diff --git a/src/routes/projects/animaldex/+page.svelte b/src/routes/projects/animaldex/+page.svelte
index 0123d38..ebadee5 100644
--- a/src/routes/projects/animaldex/+page.svelte
+++ b/src/routes/projects/animaldex/+page.svelte
@@ -1,8 +1,9 @@
 <script lang="ts">
-	import { onMount, onDestroy, tick } from 'svelte';
+	import { onMount, onDestroy } from 'svelte';
 	import { resolve } from '$app/paths';
 	import { page } from '$app/state';
-	import ArrowRight from 'lucide-svelte/icons/arrow-right';
+	import { goto, preloadData, pushState } from '$app/navigation';
+	import AnimalDetails from '$lib/animaldex/AnimalDetails.svelte';
 	import PawPrint from 'lucide-svelte/icons/paw-print';
 	import X from 'lucide-svelte/icons/x';
 	import type { Map as MaptilerMap, Marker as MaptilerMarker } from '@maptiler/sdk';
@@ -32,7 +33,7 @@
 	}
 
 	let mapContainer: HTMLDivElement;
-	let detailsSection = $state<HTMLDivElement | null>(null);
+	let detailsDialog: HTMLDialogElement;
 	let map: MaptilerMap | null = null;
 	let destroyed = false;
 	let htmlMarkers: MaptilerMarker[] = [];
@@ -52,23 +53,40 @@
 	let filterTo = $state('');
 	let showFilters = $state(false);
 
-	let selected = $state<{
-		animalId: number;
-		species: string;
-		breed: string | null;
-		animalName: string | null;
-		sightingCount: number;
-		trail: TrailPoint[];
-	} | null>(null);
-
 	function parseTrail(raw: string | TrailPoint[]): TrailPoint[] {
 		return typeof raw === 'string' ? JSON.parse(raw) : raw;
 	}
 
-	async function selectAnimal(feature: GeoJSONFeature) {
-		selected = { ...feature.properties, trail: parseTrail(feature.properties.trail) };
-		await tick();
-		detailsSection?.scrollIntoView({ block: 'nearest' });
+	// Open the animal's page as a modal over the map (shallow routing), so the map keeps its
+	// position. Reloading or sharing the URL shows the dedicated page instead.
+	async function openAnimal(animalId: number) {
+		const id = String(animalId);
+		const result = await preloadData(resolve('/projects/animaldex/[id=integer]', { id }));
+		if (result.type === 'loaded' && result.status === 200) {
+			pushState(resolve('/projects/animaldex/[id=integer]', { id }), {
+				animal: result.data.animal
+			});
+		} else {
+			goto(resolve('/projects/animaldex/[id=integer]', { id }));
+		}
+	}
+
+	function onAnimalLinkClick(event: MouseEvent, animalId: number) {
+		if (event.metaKey || event.ctrlKey || event.shiftKey || event.button !== 0) return;
+		event.preventDefault();
+		openAnimal(animalId);
+	}
+
+	$effect(() => {
+		if (page.state.animal) {
+			if (!detailsDialog.open) detailsDialog.showModal();
+		} else if (detailsDialog.open) {
+			detailsDialog.close();
+		}
+	});
+
+	function onDialogClose() {
+		if (page.state.animal) history.back();
 	}
 
 	onMount(() => {
@@ -233,7 +251,7 @@
 				el.style.justifyContent = 'center';
 			}
 
-			el.onclick = () => selectAnimal(feature);
+			el.onclick = () => openAnimal(props.animalId);
 
 			const marker = new Marker({ element: el })
 				.setLngLat(feature.geometry.coordinates)
@@ -244,7 +262,6 @@
 
 	function applyFilters() {
 		showFilters = false;
-		selected = null;
 		if (MapMarker) loadMarkers(MapMarker);
 	}
 	function clearFilters() {
@@ -254,7 +271,6 @@
 		filterReporter = '';
 		filterFrom = '';
 		filterTo = '';
-		selected = null;
 		if (MapMarker) loadMarkers(MapMarker);
 	}
 
@@ -399,72 +415,6 @@
 			no animals here yet. try another area.
 		</p>{/if}
 
-	{#if selected}
-		<div
-			bind:this={detailsSection}
-			class="mt-8 max-w-2xl border-t border-[var(--site-border)] pt-6"
-		>
-			{#if [...selected.trail].reverse().find((point) => point.photoUrl)?.photoUrl}
-				<div
-					class="relative mb-5 aspect-video max-h-80 overflow-hidden rounded bg-[var(--site-surface)]"
-				>
-					<img
-						src={[...selected.trail].reverse().find((point) => point.photoUrl)?.photoUrl}
-						alt={selected.animalName || selected.species}
-						class="h-full w-full object-cover"
-					/>
-					<button
-						onclick={() => (selected = null)}
-						aria-label="Close animal details"
-						class="absolute top-3 right-3 flex h-8 w-8 items-center justify-center rounded bg-black text-white"
-						><X size={18} aria-hidden="true" /></button
-					>
-				</div>
-			{/if}
-			<div>
-				<div class="mb-1 flex items-start justify-between gap-4">
-					<div>
-						<h2 class="text-2xl font-semibold">
-							{selected.animalName ?? selected.species}
-						</h2>
-						<p class="mt-1 text-base text-[var(--site-muted)]">
-							{selected.species}{selected.breed ? ` · ${selected.breed}` : ''}
-						</p>
-					</div>
-					<span class="text-base text-[var(--site-muted)]"
-						>{selected.sightingCount}
-						{selected.sightingCount === 1 ? 'sighting' : 'sightings'}</span
-					>
-				</div>
-				<button
-					type="button"
-					onclick={() => (selected = null)}
-					class="text-base underline underline-offset-4">close details</button
-				>
-				<div class="mt-5 divide-y divide-[var(--site-border)] border-t border-[var(--site-border)]">
-					{#each [...selected.trail].sort((a, b) => new Date(b.seenAt).getTime() - new Date(a.seenAt).getTime()) as s (s.id)}
-						<div class="flex flex-wrap items-center justify-between gap-2 py-3 text-base">
-							<span
-								>{new Date(s.seenAt).toLocaleDateString('nl-NL', {
-									day: 'numeric',
-									month: 'short',
-									year: 'numeric'
-								})}</span
-							>
-							{#if s.reporterName}<span class="text-[var(--site-muted)]">by {s.reporterName}</span
-								>{/if}
-						</div>
-					{/each}
-				</div>
-				<a
-					href={resolve(`/projects/animaldex/register?animalId=${selected.animalId}`)}
-					class="mt-5 inline-flex items-center gap-1 text-base underline underline-offset-4"
-				>
-					i saw this animal too <ArrowRight size={16} aria-hidden="true" />
-				</a>
-			</div>
-		</div>
-	{/if}
 	{#if visibleAnimals.length}
 		<div class="mt-10">
 			<h2 class="mb-3 text-xl font-semibold">animals in this area</h2>
@@ -475,9 +425,9 @@
 						.reverse()
 						.find((point) => point.photoUrl)?.photoUrl}
 					<li class="border-t border-[var(--site-border)]">
-						<button
-							type="button"
-							onclick={() => selectAnimal(feature)}
+						<a
+							href={resolve('/projects/animaldex/[id=integer]', { id: String(animal.animalId) })}
+							onclick={(event) => onAnimalLinkClick(event, animal.animalId)}
 							class="flex w-full items-center gap-3 py-3 text-left hover:text-[var(--site-muted)]"
 						>
 							{#if photo}<img
@@ -495,7 +445,7 @@
 									{animal.sightingCount === 1 ? 'sighting' : 'sightings'}</span
 								>
 							</span>
-						</button>
+						</a>
 					</li>
 				{/each}
 			</ul>
@@ -505,3 +455,35 @@
 		</div>
 	{/if}
 </section>
+
+<dialog
+	bind:this={detailsDialog}
+	onclose={onDialogClose}
+	onclick={(event) => {
+		if (event.target === detailsDialog) detailsDialog.close();
+	}}
+	aria-label={page.state.animal
+		? page.state.animal.animalName || page.state.animal.species
+		: 'Animal details'}
+	class="m-auto max-h-[calc(100dvh-2rem)] w-[calc(100%-2rem)] max-w-5xl overflow-y-auto rounded-xl border border-[var(--site-border)] bg-[var(--site-bg)] p-0 text-[var(--site-text)] backdrop:bg-black/70"
+>
+	{#if page.state.animal}
+		<div class="sticky top-0 z-10 flex justify-end gap-4 bg-[var(--site-bg)] px-5 py-3 sm:px-8">
+			<a
+				href={resolve('/projects/animaldex/[id=integer]', { id: String(page.state.animal.id) })}
+				data-sveltekit-reload
+				class="text-base underline underline-offset-4">open page</a
+			>
+			<button
+				type="button"
+				onclick={() => detailsDialog.close()}
+				aria-label="Close animal details"
+				class="flex h-8 w-8 items-center justify-center rounded hover:bg-[var(--site-surface)]"
+				><X size={20} aria-hidden="true" /></button
+			>
+		</div>
+		<div class="px-5 pb-8 sm:px-8">
+			<AnimalDetails animal={page.state.animal} />
+		</div>
+	{/if}
+</dialog>
diff --git a/src/routes/projects/animaldex/[id=integer]/+page.server.ts b/src/routes/projects/animaldex/[id=integer]/+page.server.ts
new file mode 100644
index 0000000..cc6d0e5
--- /dev/null
+++ b/src/routes/projects/animaldex/[id=integer]/+page.server.ts
@@ -0,0 +1,69 @@
+import { error } from '@sveltejs/kit';
+import type { PageServerLoad } from './$types';
+import { db } from '$lib/server/db';
+import { animals, photos, sightings } from '$lib/server/db/schema';
+import { and, asc, desc, eq, inArray, isNotNull, isNull } from 'drizzle-orm';
+
+export const load: PageServerLoad = async ({ params }) => {
+	const [animal] = await db
+		.select({
+			id: animals.id,
+			species: animals.species,
+			breed: animals.breed,
+			animalName: animals.animalName,
+			description: animals.description
+		})
+		.from(animals)
+		.where(
+			and(
+				eq(animals.id, Number(params.id)),
+				isNotNull(animals.acceptedAt),
+				isNull(animals.deniedAt)
+			)
+		)
+		.limit(1);
+
+	if (!animal) throw error(404, { message: 'Animal not found' });
+
+	const sightingRows = await db
+		.select({
+			id: sightings.id,
+			seenAt: sightings.seenAt,
+			reporterName: sightings.reporterName,
+			lat: sightings.lat,
+			lng: sightings.lng
+		})
+		.from(sightings)
+		.where(
+			and(
+				eq(sightings.animalId, animal.id),
+				isNotNull(sightings.acceptedAt),
+				isNull(sightings.deniedAt)
+			)
+		)
+		.orderBy(desc(sightings.seenAt));
+
+	const photoRows = sightingRows.length
+		? await db
+				.select({ id: photos.id, sightingId: photos.sightingId, url: photos.url })
+				.from(photos)
+				.where(
+					inArray(
+						photos.sightingId,
+						sightingRows.map((s) => s.id)
+					)
+				)
+				.orderBy(asc(photos.sortOrder))
+		: [];
+
+	return {
+		animal: {
+			...animal,
+			sightings: sightingRows.map((s) => ({
+				...s,
+				seenAt: s.seenAt.toISOString(),
+				photos: photoRows.filter((p) => p.sightingId === s.id)
+			}))
+		}
+	};
+};
diff --git a/src/routes/projects/animaldex/[id=integer]/+page.svelte b/src/routes/projects/animaldex/[id=integer]/+page.svelte
new file mode 100644
index 0000000..6f396a7
--- /dev/null
+++ b/src/routes/projects/animaldex/[id=integer]/+page.svelte
@@ -0,0 +1,17 @@
+<script lang="ts">
+	import { resolve } from '$app/paths';
+	import ArrowLeft from 'lucide-svelte/icons/arrow-left';
+	import AnimalDetails from '$lib/animaldex/AnimalDetails.svelte';
+
+	let { data } = $props();
+</script>
+
+<section class="mx-auto max-w-6xl px-4 py-10 sm:px-6 sm:py-14">
+	<a
+		href={resolve('/projects/animaldex')}
+		class="mb-6 inline-flex items-center gap-1 text-base underline underline-offset-4"
+	>
+		<ArrowLeft size={16} aria-hidden="true" /> back to map
+	</a>
+	<AnimalDetails animal={data.animal} />
+</section>