Crypto Kitties: from the Raise to Inbreeding
Analysis of the famous Crypto Kitties Game based on Ethereum was done using transaction on-chain data analytics on Bloxy.info platform
Crypto kitties is one of my favorite projects on Ethereum blockchain. Not just because it was tremendously popular, but because of how it was implemented, and what actual effect it is having on the blockchain development and adoption.
Loud Meow of small Kitties
23 November, early in the morning, the first real kitten appeared in the world, in the transaction 0x9e8f42799d… It looks a bit surprised, and either do we, seeing how the blockchain people forgetting about their tokens and ICO and start to buy … kittens.
In a week, almost 1/3 of all ethereum transactions were all about kittens.
The peak was at December, 10 when 103,000 crypto kittens found their happy owners. 2 million dollars were spent daily (4800 Ethers on 4, Dec). Gas price rapidly grown 5 times in a week. This was a really enthusiastic time, when everything was growing, even Ethereum price to dollar.
Crypto Kitties had a global effect on gas price, on statistics of smart contract calls, and probably on Ethereum rate as well. The word cloud of smart contract calls changed significantly from November to December, 2017. New words came to the blockchain, like giveBirth and breedWithAuto. Vanilla transfers, sweeps and trades finally were moved from the top.
Who was primary kitten buyers? Interesting enough, absolute majority of wallets, which bought kitties, received Ether in the same day for the first time. That were all new wallets! And from these new wallets, a significant share received Ether directly from Exchanges.
The histogram shows how much time required to buy a new kitten for the new wallet. The first Ether deposit on the wallet is counted as an axis origin, and the height of the bean is the number of wallets, which bought a kitten in X hours from the first deposit. The maximum is around 0.1 hour, which is pretty fast, with the average is around half an hour. Note, that after several hours the curve rapidly decreases, people did not want to wait to buy a new kitten!
Lyrical Digression
You may wonder, how we get all this information, facts and conclusions? All the data, allowing to make this research, is taken from the blockchain transactions in Ethereum network (except the picture of the kitten). The data was fetched from ethereum node and stored in a specially designed data storage ( data warehouse on Clickhouse platform from Yandex). After that it can be queried using the standard SQL requests, one of which is demonstrated as example below. Actually all dashboards and the web site bloxy.info is built on this technology, all data and diagrams that you see are fetched directly from the data storage, some are cached in memory, some are queried in the real time when you open the page.
Kitties Life as a Token
Technically each kitten is represented as token without a nominal, but with a specific ID. This model is called a Non-Fungible Tokens (NFT) and has a standard in Ethereum: ERC-721. Crypto kitties is a crypto currency with the symbol CK and address of token 0x06012c8cf97… . Quite interesting, that Crypto Kitties as the first implementation of ERC-721 has been successful from the very beginning.
As of October, 2018, there are more than a million crypto kitties in the world, owned by more than 80,000 wallet addresses. This is quite a large number, even comparing to the top ICO’s. From this point of view, CK is one of the top successful ICO on Ethereum, and what’s important, it actually works!
Kitten Clones and Followers
It took couple months for community to understand the potential of ERC-721 NFT tokens. The wave of crypto games flooded the network, with the peak in the February, 2018. Approximately 50 distinct NFT tokens is in daily operation, and most of them are just for games or entertainment purposes. However, none of them took the same large auditorium as CK:
Some clones were just direct. If we take the Birth event, which is pretty specific for crypto-kitties, and look what other token contracts emitted this event, we get approximately 10 contracts monthly.
Apart from the direct clones, there are dozens of projects, utilizing ERC-721 ability to map unique objects to the blockchain records with owners. Any identifiable object in virtual or physical space can be mapped to a token with ID and be granted, sold or traded to a wallet.
The full list of ERC-721 tokens is revealing the potential of people imagination. Only some of the names: Crypto Baseball, UnicornGo, Crypto Celebrities, Cryptons.
Some people collected “all of them”. The most active collected hundreds of ERC-721 different tokens. The address: 0xa238122… is a champion of the collected, with 110 different tokens ever owned.
You even could purchase a whole country with CCC ( crypto countries ) token! The number of countries are limited, only 247 unique tokens owned by only 134 unique token holders. Now they appear to start a new project with crypto-cities, asmore scalable.
This is the graph of transaction how the whole country (!) being sold:
This transaction pattern is a very similar to what we analyzed in Token Sale Anatomy, this is actually an ICO on ERC-721 token.
The large difference is that every item in ERC-721 token is unique and, in general, may not be comparable to each other. One kitty may cost penny, while the other hundreds of dollars, nobody knows beforehand. The way how they estimated are auctions — on smart contract, or even live auctions, where the price defined by the community. Apart from a regular Sale Auction, Crypto Kitties have the special Siring Auction Smart Contract where anybody can create a siring for breeding kittens. Two parties are participating, one receiving Ether, and the other the pregnant Kitty:
Kitty Generations
Pregnancy results in the new kitten born, apparently. New kitten “generation” is the level in a genealogy tree, starting from the “zero” level, which are artificially bred by Crypto Kitties smart contract at the beginning. There are some rules applied, prohibiting incest and direct inbreeding on the first level. However, kitten has no gender, it can be a siren for one kitty and matron for another.
At the early CK days, the zero and the first generation were the most popular, but this rapidly moved to higher generations, as people liked idea to breed new kittens. Pretty fast it comes to the stable picture, were kittens were more or less uniformly distributed for generations up to 20.
The current distribution of kittens and breeders by generation have the maximum on 4 for kittens and 10 for breeders:
Now look at the extreme case, the longest genealogy tree with the maximum generation. The top graph on the diagram shows the maximum generation of the kitten born on a specific date. Notable here, that there was some raise at March, then people lost interest to the breeding new generation, and then the interest came back.
Starting from summer 2018, and till now, very limited set of addresses continue to breed kittens with more and more generations. As of today (October, 8) they created a kitten with generation 1901. Look at this cutie! Nothing special, but it has the longest history of ancestors in the world.
Kitten Reproductive Problems
Kittens reproductive abilities are strongly dependent on the generation. This diagram shows the generation as the bubbles with the size, proportional to the number of kittens of the generation. The horizontal axis is the number of children in average for one kitten from the generation. The vertical axis is the average kitten age in generation ( in days ). All kittens having children are on this graph, more than a half of all kitten overall.
Generation form a sequential “path”, similar to the Main Sequence, invented by Hertzsprung and Russell for the stars in our universe. It is also called H-R diagram. This one i named as C-K ( Crypto-Kitties) diagram. The blockchain is a universe by itself, and it deserves to have the own diagram.
Kittens of generation 0 are created by Crypto Kitties smart contract. They are the most productive, as they reside at the maximum on the horizontal axis, which is the number of children. All other generations are significantly less productive. What is remarkable, that the generations are not randomly distributed on a diagram, but constitute a smooth curve, from generation 2 to generation 25. Most kitties are from 4 to 13 generations, they reside on the step of the curve.
From generation to generation the reproductive abilities of kitties slightly reducing, dropping to slightly more than 1 child per kitty to generation more than 25. This is dangerous for the population.
One of the reasons for bad reproductive skills in the physical nature is inbreeding, when sire and matron have many common relative up on the genealogy. We analyzed the tree for all the kitties and came to disappointing conclusion, that this problem really exists for CK and develops from generation to the generation. There is no inbreeding of level 1, when grandmother and grandfather are the same. However, there is a lot of intersection in the relatives on the higher levels.
Taking the ratio of inbreeding as the relative number of common relative for matron and sire of the kitten, express in percentage, we come to the following graph:
Inbreeding develops rather fast from 0 to 80 percent for generations 0 to 13. Then it remains stable, but for extra high generation ( high end generation kittens) it appears to be close to 100 %. Most of that kittens are young, but also they have almost all the same set of relatives. In physical world those kitties would suffer from genetic diseases and even could not have children. I sincerely wish that CK will not have this problem, but the artificial breeding on high generations may hurt the kitten population.
Good news here, is that most kitten quantity belong to generation from 4 to 15, and they are fine enough. We all wish crypto kitties the long life and growth in community!
This article was composed from the data and by analytical tools from Bloxy.info analytical engine.
Bloxy.info web site provides a set of tools for analytics, traders, companies and crypto enthusiasts.
The tools include APIs, dashboards and search engine, all available on-site, providing accurate data, indexed directly from the blockchain live node.
Bloxy mission is to make blockchain more transparent and accessible to people and businesses.
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