# The Living Dead: Time to Integrate Scavenging into Ecological Teaching

> Every animal dies, and almost every meat eater will scavenge when it gets the chance, yet ecology textbooks barely mention carrion. Two Spanish ecologists show how scavenging shapes food webs, from whale carcasses on the deep-sea floor to a 2000 kg rhino eaten down to a few bones in three and a half days, and call for it to be taught.

Summary by Kersey Lawrence, Original Wisdom. Updated 9 November 2026. Page: https://www.originalwisdom.com/tracking-literature/2015-moleon-sanchez-zapata-living-dead-time-integrate/

## Citation and access

- **Authors:** Marcos Moleón and José A. Sánchez-Zapata
- **Year published:** 2015
- **Journal or source:** BioScience
- **Full citation:** Moleón, M. and Sánchez-Zapata, J. A. 2015. The living dead: time to integrate scavenging into ecological teaching. BioScience 65(10): 1003–1010.
- **DOI:** 10.1093/biosci/biv101
- **Access status:** Publisher link only
- **Where to find it:** https://doi.org/10.1093/biosci/biv101

## Tags

- **Species:** Birds; Mammals; Reptiles
- **Behaviour and ecology:** Behaviour; Feeding; Predation; Predation risk; Scavenging
- **Methods and technology:** Literature review
- **Data type:** Existing data; Review
- **Observer qualification:** Not needed
- **Discipline:** Behaviour and ecology
- **Year published:** 2015

## Detailed keywords

- **Species:** No single species studied: the paper is about vertebrate scavengers and carrion worldwide. Main scavenger groups (table 1): vultures, other birds of prey, corvids, sea birds, large carnivores, mesocarnivores, suids, didelphids, killer whales, dolphins, crocodiles, turtles, snakes, monitors, fish (sharks, hagfishes), and invertebrates (flies, beetles, ants, leeches, amphipods, isopods, crabs, cephalopods, sea snails, sea stars, brittle stars, stone flies). Whale falls example (box 1): blue whale (Balaenoptera musculus) carcasses, hagfishes, sleeper sharks (Somniosus pacificus), amphipods, crabs and polychaete worms. African savannah example (box 2): carcasses of domestic chickens, impala (Aepyceros melamphus), nyala (Tragelaphus angasi), wildebeest (Connochaetes taurinus) and elephant (Loxodonta africana); scavengers including vultures, lion (Panthera leo), spotted hyena (Crocuta crocuta), genets and mongooses. Figure 4: a white rhino (Ceratotherium simum) carcass eaten by spotted hyenas, lions and Nile crocodiles (Crocodylus niloticus). Figure 3 shows “large scavengers of the world” with their Red List status, among them condors, vultures, brown bear, brown hyena, Eurasian lynx, leopard, lion, polar bear, spotted and striped hyenas, wolf, killer whale, eagles, Nile crocodile, American beaver and great white shark.
- **Location and habitat:** Worldwide, terrestrial and aquatic: tundra, boreal forest, temperate, Mediterranean, savanna and tropical forest biomes, freshwater, marine (the deep-sea floor for whale falls), and land and water edges. Box 2 and figure 4 describe a study in the African savannah; no country is named in this paper. The authors are at Universidad Miguel Hernández, Spain.
- **Topics:** carrion; scavenging (carcasivory); obligate and facultative scavengers; food webs and food web models; detritivory and decomposition; links between predation and scavenging; top-down and bottom-up effects; scavenging networks and nestedness; carcass size and scavenger community structure; whale falls; disease dynamics; ecosystem stability; ecosystem services; human evolution and early hominin scavenging; global change and carrion availability; vulture and apex predator declines (poisoning, shooting, power lines, wind farms, road kills, lead intoxication, habitat loss); supplementary feeding stations; sanitary regulations; ecology textbooks and higher education; a proposed textbook syllabus on scavenging. Inconsistencies in the paper: (1) the Web of Science search period is given as 1900 to 2013 for “scaveng” in the text, 1990 to 2013 for ”detritivor”, and figure 2 starts in 1969; (2) box 2 says the savannah scavenging rate is “much higher” than whale fall consumption, but then says “the latter rate is much higher”, which on the figures given (up to 4.45 kg per hour in the savannah versus about 1.7 to 2.5 kg per hour at whale falls) should read the former.
- **Statistics or models:** None
- **Data type:** Review and opinion piece (BioScience “Education” section). Existing data: a review of 20 ecology textbooks (most recent editions, listed in supplemental appendix S1) and a Web of Science title search of Ecology journals (papers to 2013). Examples drawn from published studies.

## Synopsis

### 1. What they did

Carrion (dead animals) and scavenging (eating carrion) have long been left out of classic ecology. Food webs were drawn as producers, plant eaters, meat eaters and top predators, and later detritus feeders, with no scavengers. The authors argue that this no longer matches the science, and that university teaching has not caught up.

- Textbooks. They checked the most recent editions of 20 ecology textbooks commonly used by students and found in university libraries.

- Research trend. They searched the Web of Science for papers in Ecology journals with “scaveng*“,”carrion” or “vulture” in the title, and compared the share published in 2004 to 2013 with papers on detritus feeding, decomposition, predation and plant eating.

- Review. They summarised recent evidence on why scavenging matters, with two examples in boxes: whale falls on the deep-sea floor and scavenging at carcasses in the African savannah.

- Proposal. They set out what ecology textbooks should cover on scavenging.

### 2. What they found

Textbooks

- Scavenging never appeared in any table of contents.

- Scavenging, scavenger and carrion were almost absent from the indexes: scavengers or scavenging vertebrates appeared in five books, and carrion consumption in one.

- Where scavenging was covered, it took one paragraph to barely two pages, always descriptive and tucked into sections on decay, other interactions or succession.

Research trend

- 64 papers had “scaveng*” in the title, 73% of them published from 2004 to 2013. For “carrion” (149 papers) and “vulture” (188), 52% and 65% came from that decade.

- For comparison, the shares for detritus feeding, decomposition, predation and plant eating were 50%, 39%, 52% and 35%.

What recent research shows

- Most, if not all, carnivores scavenge when they get the chance, including animals long thought never to eat carrion, such as snakes.

- Scavenging happens in all land and water ecosystems (table 1) and moves energy between land and water.

- Food webs underestimate scavenging links. More energy passes per scavenging link than per predation link, which has led to predation being overstated.

- Because predators also scavenge, scavenging can affect the populations of the animals eaten (top-down effects), and predation and scavenging are closely linked.

- Carrion plays a part in disease, scavenging networks can be highly structured, and scavenging may help stabilise ecosystems.

- Scavenging by early hominins was decisive in our own evolution, and scavengers have provided many services to people (such as disease control and ecotourism).

- Scavenging is under threat: changes in where and when carrion is available (from human food subsidies, new diseases and sanitary rules) are changing the behaviour and survival of species from insects to vultures. Research now offers guidelines for vulture feeding stations, sanitary rules, and reducing deaths at power lines and wind farms.

Whale falls (box 1)

- There is a fresh whale carcass on the sea floor every 16 to 36 km. In the first stage, which lasts months to about 5 years, hagfishes, sleeper sharks, amphipods and crabs remove about 90% of the soft tissue at about 1.7 to 2.5 kg per hour.

- Whaling has cut whale numbers and so whale falls, and some specialist whale carrion feeders have gone extinct.

African savannah (box 2)

- In a camera study of carcasses from 2 kg chickens to 4-tonne elephants, carcass size shaped the scavenger community.

- Larger carcasses took longer to eat but were eaten faster (0.14 kg per hour for small carcasses, 4.45 kg per hour for large ones). They were found sooner, and a smaller share was consumed.

- Vultures, lions and spotted hyenas ate nearly 50% of small carcasses and nearly 100% of medium and large ones. Only horns, a few hard bones and shreds of skin remained, after 1.6 to 419.1 hours. Insects and microorganisms played almost no part.

- Large carcasses drew more scavenger species (4.75 per carcass on average). Small carcasses drew the most species overall (14), probably because the dominant scavengers found them less easily; with fewer apex predators around, genets and mongooses could feed there.

- Figure 4 shows a 2000 kg white rhino, killed by another male in a fight, eaten by spotted hyenas, lions and Nile crocodiles until only a few hard bones remained three and a half days later.

### 3. What they concluded

- This is the “golden age” of scavenging research. Scavenging is a widespread, non-random and large pathway for energy, with effects from individuals to ecosystems and links to other processes.

- There is a gap between the science and what ecology students are taught. Food webs should include carrion and scavengers, both obligate (such as vultures) and facultative (predators and many others).

- Including scavenging could improve energy flow models and help with global change; for example, apex predators can smooth out swings in carrion supply that climate change is increasing.

- Box 3 proposes textbook content: basic concepts; when and where carrion is available; the evolution of scavengers, including humans; the structure and functioning of scavenger communities; what scavenging does (including nutrient cycling); links with predation; effects on coexistence and stability; global change impacts; and managing scavenging and conserving scavengers.

### 6. Other technologies, skills or innovations

- Motion-sensing cameras at carcasses (box 2, figure 4) and manned submersibles and remotely operated vehicles at whale falls (box 1). The authors note that better technology has helped recent scavenging research.

### 7. Implications for conservation (from the paper)

- Vultures and large predators are in serious danger worldwide from poisoning (intentional and unintentional), shooting, power lines and wind farms, road kills, lead poisoning and habitat loss. Conserving them will be extremely difficult without broad recognition of their ecological role and the services they provide.

- Science-based guidelines now exist for supplementary feeding stations, sanitary rules, and reducing scavenger deaths at power lines and wind farms.

- Many charismatic scavengers, especially vultures and large predators, are globally threatened (figure 3).

### 8. Implications for tracking (Original Wisdom's observations)

_These are Original Wisdom's observations, not the authors'._

- The point that most, if not all, carnivores scavenge when they can is useful when reading signs at a carcass: tracks and signs of a predator at carrion do not show that it made the kill.

- The savannah example shows how fast a carcass can disappear: a 2000 kg rhino was reduced to a few hard bones in three and a half days, so carcass sites may need to be read quickly.

## Cite this summary

Lawrence, K. 2026. Summary of: The Living Dead: Time to Integrate Scavenging into Ecological Teaching (Moleón and Sánchez-Zapata, 2015). Original Wisdom, Tracking Literature. https://www.originalwisdom.com/tracking-literature/2015-moleon-sanchez-zapata-living-dead-time-integrate/