Animal Fibers

Part of Knots and Cordage

Sinew, rawhide, and gut provide the strongest natural cordage materials available. Where plant fibers measure their strength in pounds, properly processed animal fibers measure theirs in hundreds of pounds.

Why Animal Fibers

Plant cordage is adequate for most survival tasks, but certain applications demand more. Bowstrings. Snare triggers. Fishing leaders. Sewing thread for hide garments. Lashing for tool hafting where failure means losing your axe head mid-swing. For these critical applications, animal fibers are superior in every measurable way — tensile strength, abrasion resistance, elasticity, and longevity.

The trade-off is availability and processing time. You need an animal carcass, and processing requires careful work. But once you have taken game, every carcass provides multiple types of cordage material that would be wasteful to discard.

Sinew

Sinew (tendon) is the premier animal cordage material. It is stronger than any plant fiber, naturally adhesive when wet, and separates into threads fine enough for sewing.

Types and Locations

Two types of sinew are harvested from large game:

Type	Location	Length	Best Uses
Leg sinew	Back of lower legs (Achilles tendon area)	4-8 inches	Short lashing, arrow wrapping, sewing
Back sinew (backstrap)	Two long strips running along either side of the spine	12-36 inches	Bowstrings, long cordage, bow backing

Back sinew is preferred for cordage due to its length. Leg sinew is easier to extract but shorter.

Harvesting Sinew

Back Sinew:

1. With the animal on its belly, make a shallow cut along the spine from neck to hip on one side, just through the hide.
2. Peel the hide back to expose the silvery-white sinew lying along the spine on top of the loin muscle.
3. Carefully separate the sinew from the meat using your fingers and a dull blade. Work slowly — the sinew peels away in a continuous sheet if you do not rush.
4. Remove the entire strip. It will be 1-3 inches wide and covered in a thin membrane.
5. Repeat on the other side of the spine.

Leg Sinew:

1. Skin the lower leg below the knee/hock joint.
2. The large tendon running down the back of the leg is immediately visible — a thick, white, rope-like cord.
3. Cut it free at both ends and peel it from the bone.

Processing

1. Clean: Remove all meat and membrane from the raw sinew. Scrape with a dull blade or your thumbnail.
2. Dry: Lay flat or drape over a stick in a well-ventilated area away from flies. Sinew dries in 1-3 days depending on conditions. It will become hard, translucent, and horn-like.
3. Store: Dried sinew stores indefinitely. Keep it dry and away from rodents.

Preparing for Use

Dried sinew must be separated into individual fibers before use:

1. Pound: Lay dried sinew on a hard surface and gently pound with a smooth stone until it begins to separate into white, fluffy fibers.
2. Peel: Pull individual fibers or small bundles apart by hand. Back sinew separates into surprisingly fine threads — individual fibers can be as thin as sewing thread.
3. Moisten: Before twisting or wrapping, moisten fibers with saliva or water. Wet sinew becomes pliable and slightly sticky. As it dries, it shrinks and tightens, creating a self-locking bond.

Natural Adhesive

Sinew’s self-adhesive property when wet is one of its greatest advantages. When wrapping a tool hafting or arrowhead binding, wet sinew applied tightly will shrink-fit as it dries, creating a joint that needs no additional glue or knots. This bond is remarkably strong.

Sinew Cordage

To make longer cordage from sinew:

1. Separate dried sinew into fiber bundles of consistent thickness.
2. Moisten the fibers.
3. Use the reverse-wrap (two-ply twist) method, just as with plant fibers.
4. Splice by overlapping new wet fibers against the existing cord — sinew’s natural adhesion holds the splice as it dries.
5. Allow finished cord to dry under light tension.

Strength: A two-ply sinew cord the thickness of paracord inner strand (roughly 1mm) can hold 50-80 pounds. Thicker cords scale proportionally.

Rawhide

Rawhide is untanned animal hide — skin that has been cleaned and dried without any chemical treatment. It is not technically a fiber but serves many of the same cordage functions, particularly for heavy-duty lashing.

Processing Rawhide

1. Flesh the hide: Lay the fresh hide hair-side down on a smooth log or flat surface. Scrape all meat, fat, and membrane from the inner surface using a dull scraper (bone, stone, or the back of a knife). Be thorough — remaining fat will cause rot.
2. Dehair (optional): For cordage, dehairing is preferred but not essential.
   • Ash method: Soak hide in a solution of hardwood ash and water (1 part ash to 5 parts water) for 3-5 days. Hair will slip easily when scraped.
   • Folding method: Fold hide hair-side in, keep damp in a warm place for 2-3 days until hair loosens.
3. Rinse: Wash thoroughly in clean water.
4. Dry: Stretch the hide flat on a frame or peg it to the ground and let it dry completely. It will become stiff and board-like.

Cutting Rawhide Lacing

The most useful cordage form of rawhide is continuous lacing, cut spirally from a round piece of hide:

1. Start at the outer edge of a dried piece of rawhide.
2. Cut a continuous strip in a spiral toward the center, maintaining consistent width.
3. For general lashing: cut strips 1/4 to 3/8 inch wide.
4. For heavy duty: 1/2 to 3/4 inch wide.
5. For fine work (sewing, snowshoe webbing): 1/8 inch wide.

Rawhide and Water

Rawhide softens dramatically when wet and shrinks powerfully as it dries. This is both an advantage and a hazard. Use the shrinkage to create tight lashings (wrap wet, let dry), but never use rawhide in applications where unexpected wetting could cause dangerous tightening — never as a collar, leash, or anything around a living creature’s body.

Rawhide Properties

Property	Rating
Tensile strength	Very high — 1/4” strip holds 200+ lbs
Flexibility	Stiff when dry, very pliable when wet
Water resistance	Poor — softens and eventually rots if kept wet
Shelf life	Years if kept dry
Best uses	Tool hafting, snowshoe webbing, drum heads, heavy lashing

Gut (Intestine Cordage)

Animal intestine, when cleaned and processed, produces a remarkably strong, flexible, and water-resistant cord. Historically used for bowstrings, fishing line, sutures, and musical instrument strings.

Processing

1. Clean: Slit the intestine lengthwise and wash thoroughly in clean water, removing all contents and inner mucous lining. Scrape with a dull blade if needed.
2. Cut into strips: Cut the cleaned, flattened intestine into strips 1/4 to 1/2 inch wide along its length. A single deer intestine can yield 20-30 feet of cord.
3. Twist: While still wet and pliable, twist each strip tightly along its length. The twist compresses the material and dramatically increases strength.
4. Dry under tension: Tie each twisted strip between two fixed points, pulled taut. As the gut dries, it shrinks and hardens into a round, translucent cord.
5. Oil (optional): Rubbing dried gut cord lightly with animal fat improves water resistance and flexibility.

Gut Cordage Properties

Property	Rating
Tensile strength	High — comparable to sinew
Flexibility	Good — better than rawhide when dry
Water resistance	Moderate — better than rawhide, worse than sinew
Transparency	Nearly transparent when dried — difficult for fish and game to see
Best uses	Fishing line, bowstrings, snare leaders, sutures

Fishing Leader

Dried gut cord is nearly invisible in water, making it an outstanding fishing leader material. Tie a length of gut cord between your main plant-fiber line and the hook. Fish that shy away from visible plant-fiber line will strike readily with a gut leader.

Comparison Table

Material	Strength (relative)	Processing Time	Availability	Water Resistance	Best Application
Sinew	Very high	1-3 days (drying)	Any large game	Good	Bowstrings, sewing, hafting
Rawhide	Very high	1-5 days	Any large game	Poor (softens)	Heavy lashing, webbing
Gut	High	1-2 days	Any game with intestines	Moderate	Fishing line, snares
Plant fiber	Low-moderate	Hours to weeks	Widespread	Varies	General cordage

Maximizing Yield from a Single Animal

A single deer-sized animal provides:

• Back sinew: Two strips, 18-30 inches each — enough for 1-2 bowstrings or extensive arrow wrapping.
• Leg sinew: Four pieces, 4-8 inches each — sewing thread and small lashings.
• Rawhide: 8-12 square feet of hide — hundreds of feet of cut lacing.
• Gut: 20-30 feet of intestine — 15-25 feet of dried cord.
• Brains: Enough to tan the hide (different process, but worth noting — the brains and the hide are never wasted).

Timing

Animal tissues begin decomposing within hours in warm weather. Harvest sinew, save intestines, and flesh the hide as soon as possible after the kill. In cold weather you have more time, but same-day processing is always best. Sinew can be dried on the bone if you cannot process immediately — remove the whole lower leg and hang it to dry, then extract sinew later.

Key Takeaways

• Sinew is the strongest and most versatile animal fiber — harvest both back sinew (long pieces for cordage) and leg sinew (short pieces for sewing and wrapping).
• Wet sinew is naturally adhesive and shrinks as it dries, making it self-locking for tool hafting and arrow binding.
• Rawhide provides the heaviest-duty lashing material but must be kept dry — it softens dramatically when wet.
• Gut cord is nearly invisible in water and makes excellent fishing leaders and fine-gauge cordage.
• Process animal fibers as soon as possible after harvest — decomposition begins within hours in warm conditions.
• A single deer-sized animal provides enough cordage material for weeks of survival use across multiple applications.