- Family: Brushfooted Butterflies (Four-footed Butterflies) – Nymphalidae
- Subfamily: Heliconians (Longwings) – Heliconiinae
- Wing span: Small, 29–37 mm (1.13–1.44 in.). Females larger than males (and usually with slightly darker upper side).
- Wing upper side: Orange with black blotches.
- Wing underside: Forewing orange with black blotches and spots, tip pale yellow and rust-red. Basal half of hind wing initially a rust-red area (occasionally with white blotch or area inside it), then row of black-bordered white blotches, and finally orange or pale yellow strip with dark margin. Outer wing mainly rust-red with pale yellow or orange areas. Outermost part with row of white margin blotches with rust-red rings and spots on basal side.
- Habitat: Bogs.
- Flying time: Mid-June–mid-July.
- Overwintering form: Caterpillar.
- Larval foodplant: Cranberry (Vaccinium oxycoccos) and bog rosemary (Andromeda polifolia). Also Viola sp. possible.
The cranberry fritillary, which can be found quite rarely across all of Finland, and the Arctic fritillary, which lives in rare places in northern Lapland, can be differentiated from the rest of the Heliconians by the angled corner on the margin of their hind wings. It is easiest to see when the butterflies are at rest with their wings pressed together in such a way that the hind wings stay on top of the forewings. Good marks to identify the cranberry fritillary are: 1) upper wing margin with discontinuous row of black triangles or spots, 2) underside of rear wing a colourful combination of rust-red, pale yellow and white, and 3) underside of forewing with pale yellow apex and brown stripe. The surest way to tell it apart from the mountain fritillary is to look at the dark patterning on the underside of the forewings, which on cranberry fritillary is clearly defined and strongly black.
Females lay their eggs individually on the host plant. The cranberry fritillary overwinters as a small caterpillar, cocooned on a branch of the host plant.