Is the Hadith About the Fly's Lifespan Being 40 Nights Authentic? Full Isnad Analysis & Scientific Proof
The Lifespan of a Fly — Hadith Analysis & Scientific Verification
Document Overview A full isnad (chain of transmission) analysis of the hadith attributing a forty-night lifespan to flies and placing them in Hell — including scientific verification, narrator criticism, and a final ruling on authenticity.
Table of Contents
- 1. The Hadith Text
- 2. Authenticity Ruling
- 3. Scientific Verification — Lifespan of Flies
- 4. Interpretation for Those Who Accept It
- 5. Transmission Paths — Two Narrations
- 6. Final Conclusion
1. The Hadith Text
Hadith — Reported by Anas ibn Malik “The lifespan of a fly is forty nights and all flies are in Hell except for bees.”
| Field | Detail |
|---|---|
| Narrator | Anas ibn Malik |
| Collector | Al-Haythami |
| Source | Majma’ Az-Zawa’id |
2. Authenticity Ruling
Ruling — Not Authentic The hadith is not authentic. Even though it is scientifically proven that the lifespan of most flying household insects ranges from 30 to 45 days, some of its narrations have authentic chains of transmission.
Position of Those Who Accept It Whoever accepts them has understood its interpretation to mean that the fly being in the Fire is not to punish it, but rather to punish the people of the Fire by landing on them. And God knows best.
3. Scientific Verification — Lifespan of Flies
Housefly Lifespan — General Average On average, a housefly can live around 20–25 days. Sometimes they can live up to a month.
Housefly Lifespan — Life Stages Houseflies pass through four distinct stages: egg, larva, pupa and adult. The life expectancy of a housefly is generally 15 to 30 days and depends on temperature and living conditions. Flies dwelling in warm homes and laboratories develop faster and live longer than their counterparts in the wild.
Fruit Fly Lifespan — Species Variation The lifespan of a fly can also depend on the species. For example, fruit flies live a little longer than house flies. These insects die after about 40 to 50 days. Like house flies, they can yield several generations during this time. Just one female fruit fly can produce up to 500 offspring.
4. Interpretation for Those Who Accept It
Scholarly Interpretation Whoever accepts the narrations with relatively stronger chains has understood its meaning to be: the fly being in the Fire is not to punish it, but rather to punish the people of the Fire by landing on them.
And God knows best.
5. Transmission Paths — Two Narrations
Overview This hadith was narrated in two ways, each with its own chain problems.
5.1 First Path — Mujahid ibn Jabr (Mursal)
Chain Status — Weak (Mursal) Mujahid bin Jabr, with a mursal chain of transmission, according to the preserved version of his narration, and it was narrated from him with a connected chain of transmission, through several unpreserved versions.
Al-Daraqutni stated this in his ‘Ilal.
Ruling on First Path It is a weak hadith.
Wording of the First Path “All flies will be in Hell except bees, and he forbade killing them and burning food.”
5.2 Second Path — Anas ibn Malik (Marfu’)
Overview Anas bin Malik, with a chain of transmission traceable to the Prophet, narrated from him through two paths.
5.2.1 Chain One — Abu Ya’la via Sakin ibn Abdul Aziz
Full Isnad — Chain One Abu Ya’la → Shaiban bin Farukh → Sakin bin Abdul Aziz → his father → Anas → Prophet ﷺ
“The life span of a fly is forty nights, and all flies will be in Hell except bees.”
Narrator Criticism Although Sakin bin Abdul Aziz is fine, his father Abdul Aziz bin Qais Al-Abdi was not authenticated except by Ibn Hibban, so he is not trustworthy.
Ruling on Chain One It is thought that Al-Haythami said that his men were trustworthy because of this chain of transmission, and so did Al-Busayri, but this is a laxity.
5.2.2 Chain Two — Abu Ya’la via Anbasa Al-Qass
Full Isnad — Chain Two Abu Ya’la → Abu Saeed Al-Ashja → Uqba bin Khalid → Anbasa Al-Qass → Hanzala → Anas → Prophet ﷺ
“The lifespan of a fly is forty days, and all flies are in the Fire.”
Narrator Criticism — Chain Two It is a weak chain of transmission, as:
- Anbasa is most likely Anbasa bin Saeed Al-Qattan, who is weak
- Hanzala Al-Sadosi is weak
6. Final Conclusion
Final Ruling It is not proven from a reliable source.
Most Likely Explanation It is most likely that:
- It is attributed to one of the noble companions, or
- The one who conveyed it removed it from its context, so it appeared in a way other than what was apparently intended by it.