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Hybrid animals are infertile because of the way their sex cells form. But sometimes, life finds a way.

FYI: We try to leave jargon out of our videos, but if you want to learn more about this topic, here are some handy keywords to get your googling started:
- Hybrid organisms: The offspring of two animals or plants of different breeds, varieties, species or genera.
- Mitosis: A process of cell division that produces copies of the original cell.
- Meiosis: A process of cell dividion that produces new daughter cells with half the chromosome number of the original cell.
- Sex cell, or gamete: a cell that fuses with another cell during fertilization (conception) in organisms that sexually reproduce.
- Hemiclonal transmission: The rare occurence in which only maternal DNA gets passed along during the creation of sex cells.

Species featured in this video:
- Mule, is the offspring of a male donkey (jack) and a female horse (mare)
- Liger, is a hybrid cross between a male lion (Panthera leo) and a female tiger (Panthera tigris)
- Zonkey, is the offspring of a zebra and a donkey. Zebra hybrids are generally known as zebroids
- Beefalo, also known as cattalo, is the offspring of a domestic cattle (Bos taurus) and an American buffalo (Bison bison)
- Cama, is the offspring of a male dromedary camel and a female llama.
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Credits (and Twitter handles):
Script Writer: David Goldenberg (@dgoldenberg)
Script Editor: Emily Elert (@eelert)
Video Illustrator: Chad Geran
Video Director: Emily Elert (@eelert)
Video Narrator: Emily Elert (@eelert)
With Contributions From: Henry Reich, Alex Reich, Kate Yoshida, Ever Salazar, Omkar Bhagat, Peter Reich, Rachel Becker
Music by: Nathaniel Schroeder: http://www.soundcloud.com/drschroeder

Image Credits: Liger Hercules - Ed Quinn
https://goo.gl/A8zgxO

Zonkey - Flickr user Leogirly4life
https://goo.gl/QAcza0

Cama - TaylorLlamas.com
http://goo.gl/YCY3Zd

Beefalo - Noah's Ark Animal
Sanctuary
http://www.noahs-ark.org/
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If you liked this week’s video, we think you might also like these things:
The Blitzkreiglr YouTube guys play the game Hybrid Animals: https://www.youtube.com/watch?v=g9WS5cd_59I
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References:

Ryder, O., Chemnick, L., Bowling, A., Benirschke, K. (1985). Male mule foal qualifies as the offspring of a female mule and Jack donkey. Journal of Heredity 76 (379-381). Retrieved from http://jhered.oxfordjournals.org/content/76/5/379

C.J. Zhao, Y.H. Qin, X.H. Lee, Ch. Wu (2006). Molecular and cytogenetic paternity testing of a male offspring of a hinny. Journal of Animal Breeding and Genetics,123: 403-405. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/17177697

Bucholz (2013). Colorado miracle mule foal lived short life, but was well-loved.The Denver Post. Retrieved from http://www.denverpost.com/2013/08/16/colorado-miracle-mule-foal-lived-short-life-but-was-well-loved/

Millon, L. (2016). Personal Communication.

Antczak, D. (2016). Personal Communication.

Farming erodes soil 50 times faster than it forms. We can change that, but will we?

Thanks to http://www.soylent.com/earth for sponsoring this video!

Thanks also to our supporters on https://www.patreon.com/MinuteEarth :
- Today I Found Out
- Maarten Bremer
- Jeff Straathof
- Mark Roth
- Tony Fadell
- Muhammad Shifaz
- 靛蓝字幕组
- Melissa Vigil
- Alberto Bortoni
- Valentin
- Antoine Coeur
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Credits (and Twitter handles):
Script Writer: Alex Reich (@alexhreich)
Script Editor: Rachel Becker (@RA_Becks)
Video Illustrator: Ever Salazar (@eversalazar)
Video Director: Kate Yoshida (@KateYoshida)
Video Narrator: Kate Yoshida (@KateYoshida)
With Contributions From: Henry Reich, Omkar Bhagat, Emily Elert, Peter Reich, David Goldenberg
Music by: Nathaniel Schroeder: http://www.soundcloud.com/drschroeder

_________________________________________

Like our videos?
Subscribe to MinuteEarth on YouTube: http://goo.gl/EpIDGd
Get early, exclusive access to our videos on Vessel: https://goo.gl/hgD1iJ
Support us on Patreon: https://goo.gl/ZVgLQZ

Also, say hello on:
Facebook: http://goo.gl/FpAvo6
Twitter: http://goo.gl/Y1aWVC

And find us on itunes: https://goo.gl/sfwS6n
___________________________________________

If you liked this week’s video, we think you might also like these things:
America is running out of soil: http://goo.gl/FXEzeR
Global Soil Partnership: http://goo.gl/lqGknM
Prairie STRIPS research: https://goo.gl/1uw1Yg

FYI: We try to leave jargon out of our videos, but if you want to learn more about this topic, here are some handy keywords to get your googling started:

Agricultural Soil Erosion: the wearing away of a field's topsoil by the natural physical forces of water and wind or through forces associated with farming activities, such as tillage. http://goo.gl/d0Ciwk

Conservation tillage/agriculture: a soil cultivation method in which fields are not ploughed & the previous year's crop residues are left on fields before and after planting the next crop, to reduce soil erosion and runoff. http://goo.gl/8aoizx, http://goo.gl/jmj8Ic

Soil: the upper layer of earth, in which plants grow; a dark, damp, gas-filled structure of minerals and organic matter formed by degrading rocks and decomposing organisms. http://goo.gl/Q6JOrH
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References:

A Landowner’s Guide to Prairie Conservation Strips. Accessed May 5, 2016. https://goo.gl/fN65MA

Antón, S. C., & Steadman, D. W. (2003). Mortuary patterns in burial caves on Mangaia, Cook Islands. International Journal of Osteoarchaeology, 13(3), 132-146. http://goo.gl/SIiMxy

FAO and ITPS. (2015). Status of the World’s Soil Resources (SWSR) – Main Report. Food and Agriculture Organization of the United Nations and Intergovernmental Technical Panel on Soils, Rome, Italy. http://goo.gl/fxPJi0

Kirch, P. V. (1997). Microcosmic histories: Island perspectives on" global" change. American Anthropologist, 99(1), 30-42.

Montgomery, D. R. (2007). Soil erosion and agricultural sustainability. Proceedings of the National Academy of Sciences, 104(33), 13268-13272. http://goo.gl/Si9E6g

Pimentel, D. (2006). Soil erosion: a food and environmental threat. Environment, development and sustainability, 8(1), 119-137. http://goo.gl/64FSCa

Soil Building Systems. Pickup Truck Capacities. Accessed May 5, 2016. http://goo.gl/u7sPfQ

Steadman, D. W., Antón, S. C., & Kirch, P. V. (2000). Ana Manuku: a prehistoric ritualistic site on Mangaia, Cook Islands. Antiquity, 74(286), 873-883. http://goo.gl/ZySytn

How Alan Turing's Reaction-Diffusion Model Simulates Patterns in Nature
Thanks to http://www.audible.com/minuteearth for sponsoring this video.

Asparagus Pee Survey Results: https://goo.gl/8x7abL

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If you liked this video, we think you might also like this:

Reaction Diffusion Simulation (Gray-Scott model)
https://pmneila.github.io/jsexp/grayscott/

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Credits (and Twitter handles):
Script Writer: Rachel Becker (@RA_Becks)
Script Editor: Emily Elert (@eelert)
Video Illustrator: Ever Salazar (@eversalazar)
Video Director: Emily Elert (@eelert)
Video Narrator: Emily Elert (@eelert)
With Contributions From: Henry Reich, Alex Reich, Kate Yoshida, Omkar Bhagat, Peter Reich, David Goldenberg
Music by: Nathaniel Schroeder: http://www.soundcloud.com/drschroeder

Also, special thanks to the following scientists:
Greg Barsh: Investigator, HudsonAlpha Institute for Biotechnology (http://goo.gl/RMD8o9)
Jeremy Green: Professor of developmental biology, King’s College London (https://goo.gl/Qcn8Ay)
Thomas Hiscock: Graduate student in systems biology, Harvard University (http://goo.gl/RbAWIy)
Shigeru Kondo: Professor, Osaka University (http://goo.gl/uQ2wYO)
James Sharpe: Coordinator of EMBL-CRG Systems Biology Unit and ICREA research professor (http://goo.gl/QCGul8)
Ian Stewart: Emeritus professor of mathematics, University of Warwick and author of The Mathematics of Life (http://goo.gl/rGR1R0)
Thomas Woolley: Postdoctoral scientist, St John's College Oxford (http://goo.gl/B4FZNn)

Image Credits:
- Mouse palate images provided courtesy of Jeremy Green, King’s College London.
- Digit patterns image provided courtesy of Luciano Marcon and Jelena Raspopovic.
- Angelfish and zebrafish images provided courtesy of Shigeru Kondo.
_________________________________________

Subscribe to MinuteEarth on YouTube: http://goo.gl/EpIDGd
Support us on Patreon: https://goo.gl/ZVgLQZ
Facebook: http://goo.gl/FpAvo6
Twitter: http://goo.gl/Y1aWVC
itunes: https://goo.gl/sfwS6n

___________________________________________

Here are some handy keywords to get your googling started:

Reaction-diffusion system: A hypothetical system in which multiple chemical substances diffuse through a defined space at different rates and react with one another, thereby generating a pattern.

Turing pattern: A periodic pattern that forms in a space where the initial distribution of ‘activator’ and ‘inhibitor’ is the same.

Morphogenesis: The processes during development that give rise to the form or shape of the organism or a structure

Alan Turing: Alan Turing was a British mathematician and the father of modern computer science. During World War II, he broke Germany’s Enigma code used to encrypt communications.

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References:

Economou, A. D., Ohazama, A., Porntaveetus, T., Sharpe, P. T., Kondo, S., Basson, M. A., … Green, J. B. A. (2012). Periodic stripe formation by a Turing-mechanism operating at growth zones in the mammalian palate. Nature Genetics, 44(3), 348–351. http://doi.org/10.1038/ng.1090

Economou, A. D., & Green, J. B. (2014). Modelling from the experimental developmental biologists viewpoint. Seminars in Cell & Developmental Biology, 35, 58-65. doi:10.1016/j.semcdb.2014.07.006

Green, J. B., & Sharpe, J. (2015). Positional information and reaction-diffusion: Two big ideas in developmental biology combine.Development, 142(7), 1203-1211. doi:10.1242/dev.114991

Kimura, Y. T. (2016, May 24). The mathematics of patterns. Retrieved from http://www.theshapeofmath.com/princeton/dynsys

Kimura, Y. T. (2014). The Mathematics of Patterns: The modeling and analysis of reaction-diffusion equations (Thesis, Princeton University). Http://www.pacm.princeton.edu/documents/Kimura.pdf.

Kondo, S., & Asai, R. (1995). A reaction-diffusion wave on the skin of the marine angelfish Pomacanthus. Nature, 376(6543), 765-768. doi:10.1038/376765a0

Kondo, S., & Miura, T. (2010). Reaction-Diffusion Model as a Framework for Understanding Biological Pattern Formation. Science, 329(5999), 1616-1620. doi:10.1126/science.1179047

Marcon, L., & Sharpe, J. (2012). Turing patterns in development: What about the horse part? Current Opinion in Genetics & Development, 22(6), 578-584. doi:10.1016/j.gde.2012.11.013

Raspopovic, J., Marcon, L., Russo, L., & Sharpe, J. (2014). Digit patterning is controlled by a Bmp-Sox9-Wnt Turing network modulated by morphogen gradients. Science, 345(6196), 566-570. doi:10.1126/science.1252960

Stewart, I. (2012). The mathematics of life. Philadelphia, PA: Basic Books. (https://goo.gl/IOagrs)

Turing, A. M. (1952). The Chemical Basis of Morphogenesis. Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences, 237(641), 37-72. Retrieved from http://www.dna.caltech.edu/courses/cs191/paperscs191/turing.pdf