The total prey biomass consumed (B) by a predator population over a defined interval is the sum, across all prey species, of the product of kill frequency, body mass, and the consumption coefficient (the carcass-utilisation efficiency).

General form:

Per-predator daily intake (kg/predator/day):

Annualised, per-predator (kg/predator/year):

Equivalent kill-rate form (when consumption coefficients are unknown, set c = 1.0 to estimate gross prey production removed):

• All kills attributable to the focal predator group are detected (or detection probability is corrected for).
• Mean body mass mᵢ reflects the actual mass of prey killed (large predators frequently kill above-mean individuals — adjust if biased).
• The consumption coefficient cᵢ accounts for scavenger loss; for solitary felids 0.65–0.80 is typical; for social canids 0.80–0.95.
• Kill counts are independent and not double-counted between cluster events.
• Time window T is biologically meaningful (e.g., a full annual cycle for migratory prey).

• Detection bias: GPS-cluster-derived kill rates miss small prey; snow-tracking misses non-snow seasons.
• Scavenger loss: Wolves, bears, and corvids may consume substantial portions of carcasses; the coefficient c only approximates this.
• Sample window: Predator kill rates vary seasonally — annualising a 90-day winter sample inflates summer estimates.
• Energetics not biomass: Biomass is not equivalent to energy; fat content varies enormously between summer and winter prey.
• Compensatory predation: Some prey killed would have died anyway (winter starvation); the metric does not separate additive from compensatory mortality.

• You have kill records (count of kills per prey species) from GPS-cluster, snow-tracking, scat, or kill-site surveys
• You know — or can estimate — mean body mass per prey species (kg)
• You want to estimate annual or per-predator prey requirements for management
• You need a publication-ready biomass estimate for a peer-reviewed wildlife journal
• You want to test whether the prey base is sufficient to support a predator recovery population
• Do NOT use if your kill detection probability is unknown — apply a correction factor first (Knopff et al. 2010)
• Do NOT use for energetic intake studies — use field metabolic rate models (Carbone & Gittleman 2002) instead
• Do NOT use if scavenger loss is significant and you have no c estimate — report gross biomass only

• Yellowstone Wolf-Elk System: Smith et al. estimated that a 10-wolf pack consumes ~88,000 kg of elk biomass per year, equivalent to ~22 elk per wolf annually.
• Yellowstone Cougars: Solo cougars consume 30–55 kg of ungulate biomass per week; a 100-cougar landscape population removes > 600 t of mule deer and elk per year.
• Florida Panther Recovery: Each panther consumes ~1,250 kg of prey biomass per year, dominated by white-tailed deer (~75%) and feral hogs (~20%).
• Greater Yellowstone Grizzlies: Adult grizzlies consume 700–1,800 kg of prey biomass per year, but ungulate biomass is only ~25–40% of total intake (vegetation and insects fill the rest).

• Detect ≥ 30 kills per predator group per season for stable estimates (Sand et al. 2008).
• For GPS-collared predators: cluster-search ≥ 80% of clusters > 4 hours.
• Use scat-based DNA + biomass conversion for cryptic predators (Mumma et al. 2014).
• Replicate across ≥ 2 seasons to capture seasonal variation in prey selection.
• Pair with prey density estimates (DistANCE sampling, line transects) to compute predation rate.

1. Enter your data — paste kill counts, body masses, and consumption coefficients in the three textareas, or use Column Entry mode for row-by-row input. Example: 52 elk, 48 mule deer, 18 bison killed by a 10-wolf pack in 365 days.
2. Choose a sample dataset — five US wildlife scenarios are pre-loaded (Yellowstone wolf, Yellowstone cougar, GYE grizzly, Northern Rockies wolf, Florida panther).
3. Configure the analysis — set your predator count (P), the time period (T, in days), and an optional study area name. The group name (e.g., "Lamar Canyon Pack") is editable.
4. Click Run Analysis — the tool computes total biomass B, per-predator daily intake I, annual per-predator intake A, and per-species contributions.
5. Read the summary cards — green = abundant biomass intake (typical of intact prey base); amber = moderate; red = below the IUCN minimum prey-availability threshold.
6. Read the full results table — total biomass, per-predator daily/annual intake, and a breakdown of every prey species' contribution.
7. Examine all four charts — biomass per species, proportional contribution, kills vs biomass, and a cumulative biomass curve.
8. Read the detailed interpretation — five paragraphs explaining what was found, the magnitude, ecosystem context, practical relevance, and limitations.
9. Copy a reporting example — use Ecology Journal style for peer review, Plain-Language for managers, and Conference Abstract for posters.
10. Export your results — Word/Doc for a written report, PDF for printing or archiving. Both files are auto-named with your study area.